diff --git a/protobuf-api/src/main/java/com/google/protobuf/AbstractMessageInternal.java b/protobuf-api/src/main/java/com/google/protobuf/AbstractMessageInternal.java
new file mode 100644
index 0000000..3e9d6be
--- /dev/null
+++ b/protobuf-api/src/main/java/com/google/protobuf/AbstractMessageInternal.java
@@ -0,0 +1,554 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+
+package com.google.protobuf;
+
+import com.google.protobuf.Descriptors.EnumValueDescriptor;
+import com.google.protobuf.Descriptors.FieldDescriptor;
+import com.google.protobuf.Descriptors.OneofDescriptor;
+import com.google.protobuf.Internal.EnumLite;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * A partial implementation of the {@link Message} interface which implements as many methods of
+ * that interface as possible in terms of other methods.
+ *
+ * @author kenton@google.com Kenton Varda
+ */
+abstract class AbstractMessageInternal
+    // TODO: Update GeneratedMessage to parameterize with MessageType and BuilderType.
+    extends AbstractMessageLite implements Message {
+
+  @Override
+  public boolean isInitialized() {
+    return MessageReflection.isInitialized(this);
+  }
+
+  /**
+   * Interface for the parent of a Builder that allows the builder to communicate invalidations back
+   * to the parent for use when using nested builders.
+   */
+  protected interface BuilderParent extends Message.BuilderParent{
+
+    /**
+     * A builder becomes dirty whenever a field is modified -- including fields in nested builders
+     * -- and becomes clean when build() is called. Thus, when a builder becomes dirty, all its
+     * parents become dirty as well, and when it becomes clean, all its children become clean. The
+     * dirtiness state is used to invalidate certain cached values.
+     *
+     * <p>To this end, a builder calls markDirty() on its parent whenever it transitions from clean
+     * to dirty. The parent must propagate this call to its own parent, unless it was already dirty,
+     * in which case the grandparent must necessarily already be dirty as well. The parent can only
+     * transition back to "clean" after calling build() on all children.
+     */
+    void markDirty();
+  }
+
+  @Override
+  public List<String> findInitializationErrors() {
+    return MessageReflection.findMissingFields(this);
+  }
+
+  @Override
+  public String getInitializationErrorString() {
+    return MessageReflection.delimitWithCommas(findInitializationErrors());
+  }
+
+  // TODO: Clear it when all subclasses have implemented this method.
+  @Override
+  public boolean hasOneof(OneofDescriptor oneof) {
+    throw new UnsupportedOperationException("hasOneof() is not implemented.");
+  }
+
+  // TODO: Clear it when all subclasses have implemented this method.
+  @Override
+  public FieldDescriptor getOneofFieldDescriptor(OneofDescriptor oneof) {
+    throw new UnsupportedOperationException("getOneofFieldDescriptor() is not implemented.");
+  }
+
+  @Override
+  public final String toString() {
+    return TextFormatInternal.printer().printToString(this);
+  }
+
+  @Override
+  public void writeTo(final CodedOutputStream output) throws IOException {
+    MessageReflection.writeMessageTo(this, getAllFields(), output, false);
+  }
+
+  protected int memoizedSize = -1;
+
+  @Override
+  int getMemoizedSerializedSize() {
+    return memoizedSize;
+  }
+
+  @Override
+  void setMemoizedSerializedSize(int size) {
+    memoizedSize = size;
+  }
+
+  @Override
+  public int getSerializedSize() {
+    int size = memoizedSize;
+    if (size != -1) {
+      return size;
+    }
+
+    memoizedSize = MessageReflection.getSerializedSize(this, getAllFields());
+    return memoizedSize;
+  }
+
+  @Override
+  public boolean equals(final Object other) {
+    if (other == this) {
+      return true;
+    }
+    if (!(other instanceof Message)) {
+      return false;
+    }
+    final Message otherMessage = (Message) other;
+    if (getDescriptorForType() != otherMessage.getDescriptorForType()) {
+      return false;
+    }
+    return compareFields(getAllFields(), otherMessage.getAllFields())
+        && getUnknownFields().equals(otherMessage.getUnknownFields());
+  }
+
+  @Override
+  public int hashCode() {
+    int hash = memoizedHashCode;
+    if (hash == 0) {
+      hash = 41;
+      hash = (19 * hash) + getDescriptorForType().hashCode();
+      hash = hashFields(hash, getAllFields());
+      hash = (29 * hash) + getUnknownFields().hashCode();
+      memoizedHashCode = hash;
+    }
+    return hash;
+  }
+
+  private static ByteString toByteString(Object value) {
+    if (value instanceof byte[]) {
+      return ByteString.copyFrom((byte[]) value);
+    } else {
+      return (ByteString) value;
+    }
+  }
+
+  /**
+   * Compares two bytes fields. The parameters must be either a byte array or a ByteString object.
+   * They can be of different type though.
+   */
+  private static boolean compareBytes(Object a, Object b) {
+    if (a instanceof byte[] && b instanceof byte[]) {
+      return Arrays.equals((byte[]) a, (byte[]) b);
+    }
+    return toByteString(a).equals(toByteString(b));
+  }
+
+  /** Converts a list of MapEntry messages into a Map used for equals() and hashCode(). */
+  @SuppressWarnings({"rawtypes", "unchecked"})
+  private static Map convertMapEntryListToMap(List list) {
+    if (list.isEmpty()) {
+      return Collections.emptyMap();
+    }
+    Map result = new HashMap<>();
+    Iterator iterator = list.iterator();
+    Message entry = (Message) iterator.next();
+    Descriptors.Descriptor descriptor = entry.getDescriptorForType();
+    FieldDescriptor key = descriptor.findFieldByName("key");
+    FieldDescriptor value = descriptor.findFieldByName("value");
+    Object fieldValue = entry.getField(value);
+    if (fieldValue instanceof EnumValueDescriptor) {
+      fieldValue = ((EnumValueDescriptor) fieldValue).getNumber();
+    }
+    result.put(entry.getField(key), fieldValue);
+    while (iterator.hasNext()) {
+      entry = (Message) iterator.next();
+      fieldValue = entry.getField(value);
+      if (fieldValue instanceof EnumValueDescriptor) {
+        fieldValue = ((EnumValueDescriptor) fieldValue).getNumber();
+      }
+      result.put(entry.getField(key), fieldValue);
+    }
+    return result;
+  }
+
+  /** Compares two map fields. The parameters must be a list of MapEntry messages. */
+  @SuppressWarnings({"rawtypes", "unchecked"})
+  private static boolean compareMapField(Object a, Object b) {
+    Map ma = convertMapEntryListToMap((List) a);
+    Map mb = convertMapEntryListToMap((List) b);
+    return MapFieldLite.equals(ma, mb);
+  }
+
+  /**
+   * Compares two sets of fields. This method is used to implement {@link
+   * AbstractMessageInternal#equals(Object)} and {@link AbstractMutableMessage#equals(Object)}. It takes
+   * special care of bytes fields because immutable messages and mutable messages use different Java
+   * type to represent a bytes field and this method should be able to compare immutable messages,
+   * mutable messages and also an immutable message to a mutable message.
+   */
+  static boolean compareFields(Map<FieldDescriptor, Object> a, Map<FieldDescriptor, Object> b) {
+    if (a.size() != b.size()) {
+      return false;
+    }
+    for (FieldDescriptor descriptor : a.keySet()) {
+      if (!b.containsKey(descriptor)) {
+        return false;
+      }
+      Object value1 = a.get(descriptor);
+      Object value2 = b.get(descriptor);
+      if (descriptor.getType() == FieldDescriptor.Type.BYTES) {
+        if (descriptor.isRepeated()) {
+          List<?> list1 = (List) value1;
+          List<?> list2 = (List) value2;
+          if (list1.size() != list2.size()) {
+            return false;
+          }
+          for (int i = 0; i < list1.size(); i++) {
+            if (!compareBytes(list1.get(i), list2.get(i))) {
+              return false;
+            }
+          }
+        } else {
+          // Compares a singular bytes field.
+          if (!compareBytes(value1, value2)) {
+            return false;
+          }
+        }
+      } else if (descriptor.isMapField()) {
+        if (!compareMapField(value1, value2)) {
+          return false;
+        }
+      } else {
+        // Compare non-bytes fields.
+        if (!value1.equals(value2)) {
+          return false;
+        }
+      }
+    }
+    return true;
+  }
+
+  /** Calculates the hash code of a map field. {@code value} must be a list of MapEntry messages. */
+  @SuppressWarnings("unchecked")
+  private static int hashMapField(Object value) {
+    return MapFieldLite.calculateHashCodeForMap(convertMapEntryListToMap((List) value));
+  }
+
+  /** Get a hash code for given fields and values, using the given seed. */
+  @SuppressWarnings("unchecked")
+  protected static int hashFields(int hash, Map<FieldDescriptor, Object> map) {
+    for (Map.Entry<FieldDescriptor, Object> entry : map.entrySet()) {
+      FieldDescriptor field = entry.getKey();
+      Object value = entry.getValue();
+      hash = (37 * hash) + field.getNumber();
+      if (field.isMapField()) {
+        hash = (53 * hash) + hashMapField(value);
+      } else if (field.getType() != FieldDescriptor.Type.ENUM) {
+        hash = (53 * hash) + value.hashCode();
+      } else if (field.isRepeated()) {
+        List<? extends EnumLite> list = (List<? extends EnumLite>) value;
+        hash = (53 * hash) + Internal.hashEnumList(list);
+      } else {
+        hash = (53 * hash) + Internal.hashEnum((EnumLite) value);
+      }
+    }
+    return hash;
+  }
+
+  /**
+   * Package private helper method for AbstractParser to create UninitializedMessageException with
+   * missing field information.
+   */
+  @Override
+  UninitializedMessageException newUninitializedMessageException() {
+    return Builder.newUninitializedMessageException(this);
+  }
+
+  // =================================================================
+
+  /**
+   * A partial implementation of the {@link Message.Builder} interface which implements as many
+   * methods of that interface as possible in terms of other methods.
+   */
+  @SuppressWarnings("unchecked")
+  public abstract static class Builder<BuilderType extends Builder<BuilderType>>
+      extends AbstractMessageLite.Builder implements Message.Builder {
+    // The compiler produces an error if this is not declared explicitly.
+    // Method isn't abstract to bypass Java 1.6 compiler issue:
+    //     http://bugs.java.com/view_bug.do?bug_id=6908259
+    @Override
+    public BuilderType clone() {
+      throw new UnsupportedOperationException("clone() should be implemented in subclasses.");
+    }
+
+    /** TODO: Clear it when all subclasses have implemented this method. */
+    @Override
+    public boolean hasOneof(OneofDescriptor oneof) {
+      throw new UnsupportedOperationException("hasOneof() is not implemented.");
+    }
+
+    /** TODO: Clear it when all subclasses have implemented this method. */
+    @Override
+    public FieldDescriptor getOneofFieldDescriptor(OneofDescriptor oneof) {
+      throw new UnsupportedOperationException("getOneofFieldDescriptor() is not implemented.");
+    }
+
+    /** TODO: Clear it when all subclasses have implemented this method. */
+    @Override
+    public BuilderType clearOneof(OneofDescriptor oneof) {
+      throw new UnsupportedOperationException("clearOneof() is not implemented.");
+    }
+
+    @Override
+    public BuilderType clear() {
+      for (final Map.Entry<FieldDescriptor, Object> entry : getAllFields().entrySet()) {
+        clearField(entry.getKey());
+      }
+      return (BuilderType) this;
+    }
+
+    @Override
+    public List<String> findInitializationErrors() {
+      return MessageReflection.findMissingFields(this);
+    }
+
+    @Override
+    public String getInitializationErrorString() {
+      return MessageReflection.delimitWithCommas(findInitializationErrors());
+    }
+
+    @Override
+    protected BuilderType internalMergeFrom(AbstractMessageLite other) {
+      return mergeFrom((Message) other);
+    }
+
+    @Override
+    public BuilderType mergeFrom(final Message other) {
+      return mergeFrom(other, other.getAllFields());
+    }
+
+    BuilderType mergeFrom(final Message other, Map<FieldDescriptor, Object> allFields) {
+      if (other.getDescriptorForType() != getDescriptorForType()) {
+        throw new IllegalArgumentException(
+            "mergeFrom(Message) can only merge messages of the same type.");
+      }
+
+      // Note:  We don't attempt to verify that other's fields have valid
+      //   types.  Doing so would be a losing battle.  We'd have to verify
+      //   all sub-messages as well, and we'd have to make copies of all of
+      //   them to insure that they don't change after verification (since
+      //   the Message interface itself cannot enforce immutability of
+      //   implementations).
+
+      for (final Map.Entry<FieldDescriptor, Object> entry : allFields.entrySet()) {
+        final FieldDescriptor field = entry.getKey();
+        if (field.isRepeated()) {
+          for (final Object element : (List) entry.getValue()) {
+            addRepeatedField(field, element);
+          }
+        } else if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+          final Message existingValue = (Message) getField(field);
+          if (existingValue == existingValue.getDefaultInstanceForType()) {
+            setField(field, entry.getValue());
+          } else {
+            setField(
+                field,
+                existingValue
+                    .newBuilderForType()
+                    .mergeFrom(existingValue)
+                    .mergeFrom((Message) entry.getValue())
+                    .build());
+          }
+        } else {
+          setField(field, entry.getValue());
+        }
+      }
+
+      mergeUnknownFields(other.getUnknownFields());
+
+      return (BuilderType) this;
+    }
+
+    @Override
+    public BuilderType mergeFrom(final CodedInputStream input) throws IOException {
+      return mergeFrom(input, ExtensionRegistry.getEmptyRegistry());
+    }
+
+    @Override
+    public BuilderType mergeFrom(
+        final CodedInputStream input, final ExtensionRegistryLite extensionRegistry)
+        throws IOException {
+      boolean discardUnknown = input.shouldDiscardUnknownFields();
+      final UnknownFieldSet.Builder unknownFields =
+          discardUnknown ? null : getUnknownFieldSetBuilder();
+      MessageReflection.mergeMessageFrom(this, unknownFields, input, extensionRegistry);
+      if (unknownFields != null) {
+        setUnknownFieldSetBuilder(unknownFields);
+      }
+      return (BuilderType) this;
+    }
+
+    protected UnknownFieldSet.Builder getUnknownFieldSetBuilder() {
+      return UnknownFieldSet.newBuilder(getUnknownFields());
+    }
+
+    protected void setUnknownFieldSetBuilder(final UnknownFieldSet.Builder builder) {
+      setUnknownFields(builder.build());
+    }
+
+    @Override
+    public BuilderType mergeUnknownFields(final UnknownFieldSet unknownFields) {
+      setUnknownFields(
+          UnknownFieldSet.newBuilder(getUnknownFields()).mergeFrom(unknownFields).build());
+      return (BuilderType) this;
+    }
+
+    @Override
+    public Message.Builder getFieldBuilder(final FieldDescriptor field) {
+      throw new UnsupportedOperationException(
+          "getFieldBuilder() called on an unsupported message type.");
+    }
+
+    @Override
+    public Message.Builder getRepeatedFieldBuilder(final FieldDescriptor field, int index) {
+      throw new UnsupportedOperationException(
+          "getRepeatedFieldBuilder() called on an unsupported message type.");
+    }
+
+    @Override
+    public String toString() {
+      return TextFormatInternal.printer().printToString(this);
+    }
+
+    /** Construct an UninitializedMessageException reporting missing fields in the given message. */
+    protected static UninitializedMessageException newUninitializedMessageException(
+        Message message) {
+      return new UninitializedMessageException(MessageReflection.findMissingFields(message));
+    }
+
+    // ===============================================================
+    // The following definitions seem to be required in order to make javac
+    // not produce weird errors like:
+    //
+    // java/com/google/protobuf/DynamicMessage.java:203: types
+    //   com.google.protobuf.AbstractMessage.Builder<
+    //     com.google.protobuf.DynamicMessage.Builder> and
+    //   com.google.protobuf.AbstractMessage.Builder<
+    //     com.google.protobuf.DynamicMessage.Builder> are incompatible; both
+    //   define mergeFrom(com.google.protobuf.ByteString), but with unrelated
+    //   return types.
+    //
+    // Strangely, these lines are only needed if javac is invoked separately
+    // on AbstractMessage.java and AbstractMessageLite.java.  If javac is
+    // invoked on both simultaneously, it works.  (Or maybe the important
+    // point is whether or not DynamicMessage.java is compiled together with
+    // AbstractMessageLite.java -- not sure.)  I suspect this is a compiler
+    // bug.
+
+    @Override
+    public BuilderType mergeFrom(final ByteString data) throws InvalidProtocolBufferException {
+      return (BuilderType) super.mergeFrom(data);
+    }
+
+    @Override
+    public BuilderType mergeFrom(
+        final ByteString data, final ExtensionRegistryLite extensionRegistry)
+        throws InvalidProtocolBufferException {
+      return (BuilderType) super.mergeFrom(data, extensionRegistry);
+    }
+
+    @Override
+    public BuilderType mergeFrom(final byte[] data) throws InvalidProtocolBufferException {
+      return (BuilderType) super.mergeFrom(data);
+    }
+
+    @Override
+    public BuilderType mergeFrom(final byte[] data, final int off, final int len)
+        throws InvalidProtocolBufferException {
+      return (BuilderType) super.mergeFrom(data, off, len);
+    }
+
+    @Override
+    public BuilderType mergeFrom(final byte[] data, final ExtensionRegistryLite extensionRegistry)
+        throws InvalidProtocolBufferException {
+      return (BuilderType) super.mergeFrom(data, extensionRegistry);
+    }
+
+    @Override
+    public BuilderType mergeFrom(
+        final byte[] data,
+        final int off,
+        final int len,
+        final ExtensionRegistryLite extensionRegistry)
+        throws InvalidProtocolBufferException {
+      return (BuilderType) super.mergeFrom(data, off, len, extensionRegistry);
+    }
+
+    @Override
+    public BuilderType mergeFrom(final InputStream input) throws IOException {
+      return (BuilderType) super.mergeFrom(input);
+    }
+
+    @Override
+    public BuilderType mergeFrom(
+        final InputStream input, final ExtensionRegistryLite extensionRegistry) throws IOException {
+      return (BuilderType) super.mergeFrom(input, extensionRegistry);
+    }
+  }
+
+  /**
+   * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
+   * generated code.
+   */
+  @Deprecated
+  protected static int hashLong(long n) {
+    return (int) (n ^ (n >>> 32));
+  }
+
+  /**
+   * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
+   * generated code.
+   */
+  @Deprecated
+  protected static int hashBoolean(boolean b) {
+    return b ? 1231 : 1237;
+  }
+
+  /**
+   * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
+   * generated code.
+   */
+  @Deprecated
+  protected static int hashEnum(EnumLite e) {
+    return e.getNumber();
+  }
+
+  /**
+   * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
+   * generated code.
+   */
+  @Deprecated
+  protected static int hashEnumList(List<? extends EnumLite> list) {
+    int hash = 1;
+    for (EnumLite e : list) {
+      hash = 31 * hash + hashEnum(e);
+    }
+    return hash;
+  }
+}
diff --git a/protobuf-api/src/main/java/com/google/protobuf/AbstractMessageLite.java b/protobuf-api/src/main/java/com/google/protobuf/AbstractMessageLite.java
index 6a9d7ba..4e3f68f 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/AbstractMessageLite.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/AbstractMessageLite.java
@@ -248,62 +248,6 @@ public BuilderType mergeFrom(
       return (BuilderType) this;
     }
 
-    /**
-     * An InputStream implementations which reads from some other InputStream but is limited to a
-     * particular number of bytes. Used by mergeDelimitedFrom(). This is intentionally
-     * package-private so that UnknownFieldSet can share it.
-     */
-    static final class LimitedInputStream extends FilterInputStream {
-      private int limit;
-
-      LimitedInputStream(InputStream in, int limit) {
-        super(in);
-        this.limit = limit;
-      }
-
-      @Override
-      public int available() throws IOException {
-        return Math.min(super.available(), limit);
-      }
-
-      @Override
-      public int read() throws IOException {
-        if (limit <= 0) {
-          return -1;
-        }
-        final int result = super.read();
-        if (result >= 0) {
-          --limit;
-        }
-        return result;
-      }
-
-      @Override
-      public int read(final byte[] b, final int off, int len) throws IOException {
-        if (limit <= 0) {
-          return -1;
-        }
-        len = Math.min(len, limit);
-        final int result = super.read(b, off, len);
-        if (result >= 0) {
-          limit -= result;
-        }
-        return result;
-      }
-
-      @Override
-      public long skip(final long n) throws IOException {
-        // because we take the minimum of an int and a long, result is guaranteed to be
-        // less than or equal to Integer.MAX_INT so this cast is safe
-        int result = (int) super.skip(Math.min(n, limit));
-        if (result >= 0) {
-          // if the superclass adheres to the contract for skip, this condition is always true
-          limit -= result;
-        }
-        return result;
-      }
-    }
-
     @Override
     public boolean mergeDelimitedFrom(
         final InputStream input, final ExtensionRegistryLite extensionRegistry) throws IOException {
diff --git a/protobuf-api/src/main/java/com/google/protobuf/AbstractParser.java b/protobuf-api/src/main/java/com/google/protobuf/AbstractParser.java
index a1cfc61..8cbe6fa 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/AbstractParser.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/AbstractParser.java
@@ -7,7 +7,6 @@
 
 package com.google.protobuf;
 
-import com.google.protobuf.AbstractMessageLite.Builder.LimitedInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.ByteBuffer;
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/Any.java b/protobuf-api/src/main/java/com/google/protobuf/Any.java
similarity index 96%
rename from protobuf-sdk/src/main/java/com/google/protobuf/Any.java
rename to protobuf-api/src/main/java/com/google/protobuf/Any.java
index 74c8085..0573c59 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/Any.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/Any.java
@@ -96,12 +96,12 @@
  * Protobuf type {@code google.protobuf.Any}
  */
 public final class Any extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.Any)
     AnyOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use Any.newBuilder() to construct.
-  private Any(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private Any(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private Any() {
@@ -122,7 +122,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.AnyProto.internal_static_google_protobuf_Any_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -355,8 +355,8 @@ public final boolean isInitialized() {
   @java.lang.Override
   public void writeTo(com.google.protobuf.CodedOutputStream output)
                       throws java.io.IOException {
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(typeUrl_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 1, typeUrl_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(typeUrl_)) {
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, typeUrl_);
     }
     if (!value_.isEmpty()) {
       output.writeBytes(2, value_);
@@ -370,8 +370,8 @@ public int getSerializedSize() {
     if (size != -1) return size;
 
     size = 0;
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(typeUrl_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, typeUrl_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(typeUrl_)) {
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(1, typeUrl_);
     }
     if (!value_.isEmpty()) {
       size += com.google.protobuf.CodedOutputStream
@@ -450,20 +450,20 @@ public static com.google.protobuf.Any parseFrom(
   }
   public static com.google.protobuf.Any parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Any parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.Any parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -471,20 +471,20 @@ public static com.google.protobuf.Any parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.Any parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Any parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -504,7 +504,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -600,7 +600,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.Any}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.Any)
       com.google.protobuf.AnyOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -609,7 +609,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.AnyProto.internal_static_google_protobuf_Any_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -622,7 +622,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/AnyOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/AnyOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/AnyOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/AnyOrBuilder.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/AnyProto.java b/protobuf-api/src/main/java/com/google/protobuf/AnyProto.java
similarity index 92%
rename from protobuf-sdk/src/main/java/com/google/protobuf/AnyProto.java
rename to protobuf-api/src/main/java/com/google/protobuf/AnyProto.java
index 2121cd2..bdb1d0d 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/AnyProto.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/AnyProto.java
@@ -18,7 +18,7 @@ public static void registerAllExtensions(
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_Any_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_Any_fieldAccessorTable;
 
   public static com.google.protobuf.Descriptors.FileDescriptor
@@ -43,7 +43,7 @@ public static void registerAllExtensions(
     internal_static_google_protobuf_Any_descriptor =
       getDescriptor().getMessageTypes().get(0);
     internal_static_google_protobuf_Any_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_Any_descriptor,
         new java.lang.String[] { "TypeUrl", "Value", });
   }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/Api.java b/protobuf-api/src/main/java/com/google/protobuf/Api.java
similarity index 95%
rename from protobuf-sdk/src/main/java/com/google/protobuf/Api.java
rename to protobuf-api/src/main/java/com/google/protobuf/Api.java
index afd6947..9471f31 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/Api.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/Api.java
@@ -20,12 +20,12 @@
  * Protobuf type {@code google.protobuf.Api}
  */
 public final class Api extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.Api)
     ApiOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use Api.newBuilder() to construct.
-  private Api(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private Api(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private Api() {
@@ -50,7 +50,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.ApiProto.internal_static_google_protobuf_Api_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -454,8 +454,8 @@ public final boolean isInitialized() {
   @java.lang.Override
   public void writeTo(com.google.protobuf.CodedOutputStream output)
                       throws java.io.IOException {
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 1, name_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(name_)) {
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, name_);
     }
     for (int i = 0; i < methods_.size(); i++) {
       output.writeMessage(2, methods_.get(i));
@@ -463,8 +463,8 @@ public void writeTo(com.google.protobuf.CodedOutputStream output)
     for (int i = 0; i < options_.size(); i++) {
       output.writeMessage(3, options_.get(i));
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(version_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 4, version_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(version_)) {
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 4, version_);
     }
     if (((bitField0_ & 0x00000001) != 0)) {
       output.writeMessage(5, getSourceContext());
@@ -484,8 +484,8 @@ public int getSerializedSize() {
     if (size != -1) return size;
 
     size = 0;
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, name_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(name_)) {
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(1, name_);
     }
     for (int i = 0; i < methods_.size(); i++) {
       size += com.google.protobuf.CodedOutputStream
@@ -495,8 +495,8 @@ public int getSerializedSize() {
       size += com.google.protobuf.CodedOutputStream
         .computeMessageSize(3, options_.get(i));
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(version_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(4, version_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(version_)) {
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(4, version_);
     }
     if (((bitField0_ & 0x00000001) != 0)) {
       size += com.google.protobuf.CodedOutputStream
@@ -613,20 +613,20 @@ public static com.google.protobuf.Api parseFrom(
   }
   public static com.google.protobuf.Api parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Api parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.Api parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -634,20 +634,20 @@ public static com.google.protobuf.Api parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.Api parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Api parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -667,7 +667,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -687,7 +687,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.Api}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.Api)
       com.google.protobuf.ApiOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -696,7 +696,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.ApiProto.internal_static_google_protobuf_Api_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -709,12 +709,12 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
       maybeForceBuilderInitialization();
     }
     private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3
+      if (com.google.protobuf.GeneratedMessageV3Internal
               .alwaysUseFieldBuilders) {
         getMethodsFieldBuilder();
         getOptionsFieldBuilder();
@@ -906,7 +906,7 @@ public Builder mergeFrom(com.google.protobuf.Api other) {
             methods_ = other.methods_;
             bitField0_ = (bitField0_ & ~0x00000002);
             methodsBuilder_ = 
-              com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+              com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                  getMethodsFieldBuilder() : null;
           } else {
             methodsBuilder_.addAllMessages(other.methods_);
@@ -932,7 +932,7 @@ public Builder mergeFrom(com.google.protobuf.Api other) {
             options_ = other.options_;
             bitField0_ = (bitField0_ & ~0x00000004);
             optionsBuilder_ = 
-              com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+              com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                  getOptionsFieldBuilder() : null;
           } else {
             optionsBuilder_.addAllMessages(other.options_);
@@ -966,7 +966,7 @@ public Builder mergeFrom(com.google.protobuf.Api other) {
             mixins_ = other.mixins_;
             bitField0_ = (bitField0_ & ~0x00000020);
             mixinsBuilder_ = 
-              com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+              com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                  getMixinsFieldBuilder() : null;
           } else {
             mixinsBuilder_.addAllMessages(other.mixins_);
@@ -1186,8 +1186,8 @@ private void ensureMethodsIsMutable() {
        }
     }
 
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Method, com.google.protobuf.Method.Builder, com.google.protobuf.MethodOrBuilder> methodsBuilder_;
+    private RepeatedFieldBuilderV3Internal<
+            Method, Method.Builder, MethodOrBuilder> methodsBuilder_;
 
     /**
      * <pre>
@@ -1474,12 +1474,12 @@ public com.google.protobuf.Method.Builder addMethodsBuilder(
          getMethodsBuilderList() {
       return getMethodsFieldBuilder().getBuilderList();
     }
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Method, com.google.protobuf.Method.Builder, com.google.protobuf.MethodOrBuilder> 
+    private RepeatedFieldBuilderV3Internal<
+            Method, Method.Builder, MethodOrBuilder>
         getMethodsFieldBuilder() {
       if (methodsBuilder_ == null) {
-        methodsBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-            com.google.protobuf.Method, com.google.protobuf.Method.Builder, com.google.protobuf.MethodOrBuilder>(
+        methodsBuilder_ = new RepeatedFieldBuilderV3Internal<
+                    Method, Method.Builder, MethodOrBuilder>(
                 methods_,
                 ((bitField0_ & 0x00000002) != 0),
                 getParentForChildren(),
@@ -1498,8 +1498,8 @@ private void ensureOptionsIsMutable() {
        }
     }
 
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Option, com.google.protobuf.Option.Builder, com.google.protobuf.OptionOrBuilder> optionsBuilder_;
+    private RepeatedFieldBuilderV3Internal<
+            Option, Option.Builder, OptionOrBuilder> optionsBuilder_;
 
     /**
      * <pre>
@@ -1786,12 +1786,12 @@ public com.google.protobuf.Option.Builder addOptionsBuilder(
          getOptionsBuilderList() {
       return getOptionsFieldBuilder().getBuilderList();
     }
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Option, com.google.protobuf.Option.Builder, com.google.protobuf.OptionOrBuilder> 
+    private RepeatedFieldBuilderV3Internal<
+            Option, Option.Builder, OptionOrBuilder>
         getOptionsFieldBuilder() {
       if (optionsBuilder_ == null) {
-        optionsBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-            com.google.protobuf.Option, com.google.protobuf.Option.Builder, com.google.protobuf.OptionOrBuilder>(
+        optionsBuilder_ = new RepeatedFieldBuilderV3Internal<
+                    Option, Option.Builder, OptionOrBuilder>(
                 options_,
                 ((bitField0_ & 0x00000004) != 0),
                 getParentForChildren(),
@@ -1984,8 +1984,8 @@ public Builder setVersionBytes(
     }
 
     private com.google.protobuf.SourceContext sourceContext_;
-    private com.google.protobuf.SingleFieldBuilderV3<
-        com.google.protobuf.SourceContext, com.google.protobuf.SourceContext.Builder, com.google.protobuf.SourceContextOrBuilder> sourceContextBuilder_;
+    private SingleFieldBuilderV3Internal<
+            SourceContext, SourceContext.Builder, SourceContextOrBuilder> sourceContextBuilder_;
     /**
      * <pre>
      * Source context for the protocol buffer service represented by this
@@ -2135,12 +2135,12 @@ public com.google.protobuf.SourceContextOrBuilder getSourceContextOrBuilder() {
      *
      * <code>.google.protobuf.SourceContext source_context = 5;</code>
      */
-    private com.google.protobuf.SingleFieldBuilderV3<
-        com.google.protobuf.SourceContext, com.google.protobuf.SourceContext.Builder, com.google.protobuf.SourceContextOrBuilder> 
+    private SingleFieldBuilderV3Internal<
+            SourceContext, SourceContext.Builder, SourceContextOrBuilder>
         getSourceContextFieldBuilder() {
       if (sourceContextBuilder_ == null) {
-        sourceContextBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-            com.google.protobuf.SourceContext, com.google.protobuf.SourceContext.Builder, com.google.protobuf.SourceContextOrBuilder>(
+        sourceContextBuilder_ = new SingleFieldBuilderV3Internal<
+                    SourceContext, SourceContext.Builder, SourceContextOrBuilder>(
                 getSourceContext(),
                 getParentForChildren(),
                 isClean());
@@ -2158,8 +2158,8 @@ private void ensureMixinsIsMutable() {
        }
     }
 
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Mixin, com.google.protobuf.Mixin.Builder, com.google.protobuf.MixinOrBuilder> mixinsBuilder_;
+    private RepeatedFieldBuilderV3Internal<
+            Mixin, Mixin.Builder, MixinOrBuilder> mixinsBuilder_;
 
     /**
      * <pre>
@@ -2446,12 +2446,12 @@ public com.google.protobuf.Mixin.Builder addMixinsBuilder(
          getMixinsBuilderList() {
       return getMixinsFieldBuilder().getBuilderList();
     }
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Mixin, com.google.protobuf.Mixin.Builder, com.google.protobuf.MixinOrBuilder> 
+    private RepeatedFieldBuilderV3Internal<
+            Mixin, Mixin.Builder, MixinOrBuilder>
         getMixinsFieldBuilder() {
       if (mixinsBuilder_ == null) {
-        mixinsBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-            com.google.protobuf.Mixin, com.google.protobuf.Mixin.Builder, com.google.protobuf.MixinOrBuilder>(
+        mixinsBuilder_ = new RepeatedFieldBuilderV3Internal<
+                    Mixin, Mixin.Builder, MixinOrBuilder>(
                 mixins_,
                 ((bitField0_ & 0x00000020) != 0),
                 getParentForChildren(),
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/ApiOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/ApiOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/ApiOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/ApiOrBuilder.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/ApiProto.java b/protobuf-api/src/main/java/com/google/protobuf/ApiProto.java
similarity index 90%
rename from protobuf-sdk/src/main/java/com/google/protobuf/ApiProto.java
rename to protobuf-api/src/main/java/com/google/protobuf/ApiProto.java
index e96e7b2..aa89982 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/ApiProto.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/ApiProto.java
@@ -18,17 +18,17 @@ public static void registerAllExtensions(
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_Api_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_Api_fieldAccessorTable;
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_Method_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_Method_fieldAccessorTable;
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_Mixin_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_Mixin_fieldAccessorTable;
 
   public static com.google.protobuf.Descriptors.FileDescriptor
@@ -68,19 +68,19 @@ public static void registerAllExtensions(
     internal_static_google_protobuf_Api_descriptor =
       getDescriptor().getMessageTypes().get(0);
     internal_static_google_protobuf_Api_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_Api_descriptor,
         new java.lang.String[] { "Name", "Methods", "Options", "Version", "SourceContext", "Mixins", "Syntax", });
     internal_static_google_protobuf_Method_descriptor =
       getDescriptor().getMessageTypes().get(1);
     internal_static_google_protobuf_Method_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_Method_descriptor,
         new java.lang.String[] { "Name", "RequestTypeUrl", "RequestStreaming", "ResponseTypeUrl", "ResponseStreaming", "Options", "Syntax", });
     internal_static_google_protobuf_Mixin_descriptor =
       getDescriptor().getMessageTypes().get(2);
     internal_static_google_protobuf_Mixin_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_Mixin_descriptor,
         new java.lang.String[] { "Name", "Root", });
     com.google.protobuf.SourceContextProto.getDescriptor();
diff --git a/protobuf-api/src/main/java/com/google/protobuf/ArrayDecoders.java b/protobuf-api/src/main/java/com/google/protobuf/ArrayDecoders.java
index bf5f922..331806b 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/ArrayDecoders.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/ArrayDecoders.java
@@ -765,7 +765,7 @@ static int decodeExtensionOrUnknownField(
       throws IOException {
     final int number = tag >>> 3;
     GeneratedMessageLite.GeneratedExtension extension =
-        registers.extensionRegistry.findLiteExtensionByNumber(defaultInstance, number);
+            (GeneratedMessageLite.GeneratedExtension) registers.extensionRegistry.findLiteExtensionByNumber(defaultInstance, number);
     if (extension == null) {
       return decodeUnknownField(
           tag, data, position, limit, getMutableUnknownFields(message), registers);
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/BoolValue.java b/protobuf-api/src/main/java/com/google/protobuf/BoolValue.java
similarity index 94%
rename from protobuf-sdk/src/main/java/com/google/protobuf/BoolValue.java
rename to protobuf-api/src/main/java/com/google/protobuf/BoolValue.java
index a015e51..0034f38 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/BoolValue.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/BoolValue.java
@@ -14,12 +14,12 @@
  * Protobuf type {@code google.protobuf.BoolValue}
  */
 public final class BoolValue extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.BoolValue)
     BoolValueOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use BoolValue.newBuilder() to construct.
-  private BoolValue(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private BoolValue(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private BoolValue() {
@@ -38,7 +38,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.WrappersProto.internal_static_google_protobuf_BoolValue_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -160,20 +160,20 @@ public static com.google.protobuf.BoolValue parseFrom(
   }
   public static com.google.protobuf.BoolValue parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.BoolValue parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.BoolValue parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -181,20 +181,20 @@ public static com.google.protobuf.BoolValue parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.BoolValue parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.BoolValue parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -214,7 +214,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -228,7 +228,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.BoolValue}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.BoolValue)
       com.google.protobuf.BoolValueOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -237,7 +237,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.WrappersProto.internal_static_google_protobuf_BoolValue_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -250,7 +250,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/BoolValueOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/BoolValueOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/BoolValueOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/BoolValueOrBuilder.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/BytesValue.java b/protobuf-api/src/main/java/com/google/protobuf/BytesValue.java
similarity index 94%
rename from protobuf-sdk/src/main/java/com/google/protobuf/BytesValue.java
rename to protobuf-api/src/main/java/com/google/protobuf/BytesValue.java
index 44eaefe..9b1a079 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/BytesValue.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/BytesValue.java
@@ -14,12 +14,12 @@
  * Protobuf type {@code google.protobuf.BytesValue}
  */
 public final class BytesValue extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.BytesValue)
     BytesValueOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use BytesValue.newBuilder() to construct.
-  private BytesValue(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private BytesValue(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private BytesValue() {
@@ -39,7 +39,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.WrappersProto.internal_static_google_protobuf_BytesValue_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -160,20 +160,20 @@ public static com.google.protobuf.BytesValue parseFrom(
   }
   public static com.google.protobuf.BytesValue parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.BytesValue parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.BytesValue parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -181,20 +181,20 @@ public static com.google.protobuf.BytesValue parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.BytesValue parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.BytesValue parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -214,7 +214,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -228,7 +228,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.BytesValue}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.BytesValue)
       com.google.protobuf.BytesValueOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -237,7 +237,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.WrappersProto.internal_static_google_protobuf_BytesValue_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -250,7 +250,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/BytesValueOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/BytesValueOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/BytesValueOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/BytesValueOrBuilder.java
diff --git a/protobuf-api/src/main/java/com/google/protobuf/CodedOutputStream.java b/protobuf-api/src/main/java/com/google/protobuf/CodedOutputStream.java
index 37bb44a..5131299 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/CodedOutputStream.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/CodedOutputStream.java
@@ -159,7 +159,7 @@ public void useDeterministicSerialization() {
     serializationDeterministic = true;
   }
 
-  boolean isSerializationDeterministic() {
+  public boolean isSerializationDeterministic() {
     return serializationDeterministic;
   }
 
diff --git a/protobuf-api/src/main/java/com/google/protobuf/DescriptorProtos.java b/protobuf-api/src/main/java/com/google/protobuf/DescriptorProtos.java
index bc20823..cb2cec8 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/DescriptorProtos.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/DescriptorProtos.java
@@ -273,7 +273,7 @@ private Edition(int value) {
 
   public interface FileDescriptorSetOrBuilder extends
       // @@protoc_insertion_point(interface_extends:google.protobuf.FileDescriptorSet)
-      com.google.protobuf.GeneratedMessageV3.
+      com.google.protobuf.GeneratedMessageV3Internal.
           ExtendableMessageOrBuilder<FileDescriptorSet> {
 
     /**
@@ -309,13 +309,13 @@ com.google.protobuf.DescriptorProtos.FileDescriptorProtoOrBuilder getFileOrBuild
    * Protobuf type {@code google.protobuf.FileDescriptorSet}
    */
   public static final class FileDescriptorSet extends
-      com.google.protobuf.GeneratedMessageV3.ExtendableMessage<
+      com.google.protobuf.GeneratedMessageV3Internal.ExtendableMessage<
         FileDescriptorSet> implements
       // @@protoc_insertion_point(message_implements:google.protobuf.FileDescriptorSet)
       FileDescriptorSetOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use FileDescriptorSet.newBuilder() to construct.
-    private FileDescriptorSet(com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<com.google.protobuf.DescriptorProtos.FileDescriptorSet, ?> builder) {
+    private FileDescriptorSet(com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<com.google.protobuf.DescriptorProtos.FileDescriptorSet, ?> builder) {
       super(builder);
     }
     private FileDescriptorSet() {
@@ -335,7 +335,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FileDescriptorSet_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -407,7 +407,7 @@ public final boolean isInitialized() {
     @java.lang.Override
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
-      com.google.protobuf.GeneratedMessageV3
+      com.google.protobuf.GeneratedMessageV3Internal
         .ExtendableMessage<com.google.protobuf.DescriptorProtos.FileDescriptorSet>.ExtensionWriter
           extensionWriter = newExtensionWriter();
       for (int i = 0; i < file_.size(); i++) {
@@ -502,20 +502,20 @@ public static com.google.protobuf.DescriptorProtos.FileDescriptorSet parseFrom(
     }
     public static com.google.protobuf.DescriptorProtos.FileDescriptorSet parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.FileDescriptorSet parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.FileDescriptorSet parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -523,20 +523,20 @@ public static com.google.protobuf.DescriptorProtos.FileDescriptorSet parseDelimi
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.FileDescriptorSet parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.FileDescriptorSet parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -556,7 +556,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -569,7 +569,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.FileDescriptorSet}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<
+        com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<
           com.google.protobuf.DescriptorProtos.FileDescriptorSet, Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.FileDescriptorSet)
         com.google.protobuf.DescriptorProtos.FileDescriptorSetOrBuilder {
@@ -579,7 +579,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FileDescriptorSet_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -592,7 +592,7 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
 
       }
@@ -687,33 +687,33 @@ public Builder addRepeatedField(
           java.lang.Object value) {
         return super.addRepeatedField(field, value);
       }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.FileDescriptorSet, Type> extension,
-          Type value) {
-        return super.setExtension(extension, value);
-      }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.FileDescriptorSet, java.util.List<Type>> extension,
-          int index, Type value) {
-        return super.setExtension(extension, index, value);
-      }
-      @java.lang.Override
-      public <Type> Builder addExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.FileDescriptorSet, java.util.List<Type>> extension,
-          Type value) {
-        return super.addExtension(extension, value);
-      }
-      @java.lang.Override
-      public <T> Builder clearExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.FileDescriptorSet, T> extension) {
-        return super.clearExtension(extension);
-      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.FileDescriptorSet, Type> extension,
+//          Type value) {
+//        return super.setExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.FileDescriptorSet, java.util.List<Type>> extension,
+//          int index, Type value) {
+//        return super.setExtension(extension, index, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder addExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.FileDescriptorSet, java.util.List<Type>> extension,
+//          Type value) {
+//        return super.addExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <T> Builder clearExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.FileDescriptorSet, T> extension) {
+//        return super.clearExtension(extension);
+//      }
       @java.lang.Override
       public Builder mergeFrom(com.google.protobuf.Message other) {
         if (other instanceof com.google.protobuf.DescriptorProtos.FileDescriptorSet) {
@@ -745,7 +745,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.FileDescriptorSet
               file_ = other.file_;
               bitField0_ = (bitField0_ & ~0x00000001);
               fileBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getFileFieldBuilder() : null;
             } else {
               fileBuilder_.addAllMessages(other.file_);
@@ -826,8 +826,8 @@ private void ensureFileIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FileDescriptorProto, com.google.protobuf.DescriptorProtos.FileDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.FileDescriptorProtoOrBuilder> fileBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                FileDescriptorProto, FileDescriptorProto.Builder, FileDescriptorProtoOrBuilder> fileBuilder_;
 
       /**
        * <code>repeated .google.protobuf.FileDescriptorProto file = 1;</code>
@@ -958,7 +958,7 @@ public Builder addAllFile(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.FileDescriptorProto> values) {
         if (fileBuilder_ == null) {
           ensureFileIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, file_);
           onChanged();
         } else {
@@ -1042,12 +1042,12 @@ public com.google.protobuf.DescriptorProtos.FileDescriptorProto.Builder addFileB
            getFileBuilderList() {
         return getFileFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FileDescriptorProto, com.google.protobuf.DescriptorProtos.FileDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.FileDescriptorProtoOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                FileDescriptorProto, FileDescriptorProto.Builder, FileDescriptorProtoOrBuilder>
           getFileFieldBuilder() {
         if (fileBuilder_ == null) {
-          fileBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.FileDescriptorProto, com.google.protobuf.DescriptorProtos.FileDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.FileDescriptorProtoOrBuilder>(
+          fileBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        FileDescriptorProto, FileDescriptorProto.Builder, FileDescriptorProtoOrBuilder>(
                   file_,
                   ((bitField0_ & 0x00000001) != 0),
                   getParentForChildren(),
@@ -1531,12 +1531,12 @@ com.google.protobuf.DescriptorProtos.FieldDescriptorProtoOrBuilder getExtensionO
    * Protobuf type {@code google.protobuf.FileDescriptorProto}
    */
   public static final class FileDescriptorProto extends
-      com.google.protobuf.GeneratedMessageV3 implements
+      com.google.protobuf.GeneratedMessageV3Internal implements
       // @@protoc_insertion_point(message_implements:google.protobuf.FileDescriptorProto)
       FileDescriptorProtoOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use FileDescriptorProto.newBuilder() to construct.
-    private FileDescriptorProto(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    private FileDescriptorProto(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
       super(builder);
     }
     private FileDescriptorProto() {
@@ -1567,7 +1567,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FileDescriptorProto_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -2254,13 +2254,13 @@ public final boolean isInitialized() {
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
       if (((bitField0_ & 0x00000001) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 1, name_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, name_);
       }
       if (((bitField0_ & 0x00000002) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 2, package_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 2, package_);
       }
       for (int i = 0; i < dependency_.size(); i++) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 3, dependency_.getRaw(i));
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 3, dependency_.getRaw(i));
       }
       for (int i = 0; i < messageType_.size(); i++) {
         output.writeMessage(4, messageType_.get(i));
@@ -2287,7 +2287,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output)
         output.writeInt32(11, weakDependency_.getInt(i));
       }
       if (((bitField0_ & 0x00000010) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 12, syntax_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 12, syntax_);
       }
       if (((bitField0_ & 0x00000020) != 0)) {
         output.writeEnum(14, edition_);
@@ -2302,10 +2302,10 @@ public int getSerializedSize() {
 
       size = 0;
       if (((bitField0_ & 0x00000001) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, name_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(1, name_);
       }
       if (((bitField0_ & 0x00000002) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(2, package_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(2, package_);
       }
       {
         int dataSize = 0;
@@ -2358,7 +2358,7 @@ public int getSerializedSize() {
         size += 1 * getWeakDependencyList().size();
       }
       if (((bitField0_ & 0x00000010) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(12, syntax_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(12, syntax_);
       }
       if (((bitField0_ & 0x00000020) != 0)) {
         size += com.google.protobuf.CodedOutputStream
@@ -2524,20 +2524,20 @@ public static com.google.protobuf.DescriptorProtos.FileDescriptorProto parseFrom
     }
     public static com.google.protobuf.DescriptorProtos.FileDescriptorProto parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.FileDescriptorProto parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.FileDescriptorProto parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -2545,20 +2545,20 @@ public static com.google.protobuf.DescriptorProtos.FileDescriptorProto parseDeli
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.FileDescriptorProto parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.FileDescriptorProto parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -2578,7 +2578,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -2590,7 +2590,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.FileDescriptorProto}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+        com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.FileDescriptorProto)
         com.google.protobuf.DescriptorProtos.FileDescriptorProtoOrBuilder {
       public static final com.google.protobuf.Descriptors.Descriptor
@@ -2599,7 +2599,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FileDescriptorProto_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -2612,12 +2612,12 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
         maybeForceBuilderInitialization();
       }
       private void maybeForceBuilderInitialization() {
-        if (com.google.protobuf.GeneratedMessageV3
+        if (com.google.protobuf.GeneratedMessageV3Internal
                 .alwaysUseFieldBuilders) {
           getMessageTypeFieldBuilder();
           getEnumTypeFieldBuilder();
@@ -2899,7 +2899,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.FileDescriptorProt
               messageType_ = other.messageType_;
               bitField0_ = (bitField0_ & ~0x00000020);
               messageTypeBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getMessageTypeFieldBuilder() : null;
             } else {
               messageTypeBuilder_.addAllMessages(other.messageType_);
@@ -2925,7 +2925,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.FileDescriptorProt
               enumType_ = other.enumType_;
               bitField0_ = (bitField0_ & ~0x00000040);
               enumTypeBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getEnumTypeFieldBuilder() : null;
             } else {
               enumTypeBuilder_.addAllMessages(other.enumType_);
@@ -2951,7 +2951,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.FileDescriptorProt
               service_ = other.service_;
               bitField0_ = (bitField0_ & ~0x00000080);
               serviceBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getServiceFieldBuilder() : null;
             } else {
               serviceBuilder_.addAllMessages(other.service_);
@@ -2977,7 +2977,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.FileDescriptorProt
               extension_ = other.extension_;
               bitField0_ = (bitField0_ & ~0x00000100);
               extensionBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getExtensionFieldBuilder() : null;
             } else {
               extensionBuilder_.addAllMessages(other.extension_);
@@ -3516,7 +3516,7 @@ public Builder addDependency(
       public Builder addAllDependency(
           java.lang.Iterable<java.lang.String> values) {
         ensureDependencyIsMutable();
-        com.google.protobuf.AbstractMessageLite.Builder.addAll(
+        com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
             values, dependency_);
         bitField0_ |= 0x00000004;
         onChanged();
@@ -3647,7 +3647,7 @@ public Builder addPublicDependency(int value) {
       public Builder addAllPublicDependency(
           java.lang.Iterable<? extends java.lang.Integer> values) {
         ensurePublicDependencyIsMutable();
-        com.google.protobuf.AbstractMessageLite.Builder.addAll(
+        com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
             values, publicDependency_);
         bitField0_ |= 0x00000008;
         onChanged();
@@ -3765,7 +3765,7 @@ public Builder addWeakDependency(int value) {
       public Builder addAllWeakDependency(
           java.lang.Iterable<? extends java.lang.Integer> values) {
         ensureWeakDependencyIsMutable();
-        com.google.protobuf.AbstractMessageLite.Builder.addAll(
+        com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
             values, weakDependency_);
         bitField0_ |= 0x00000010;
         onChanged();
@@ -3796,8 +3796,8 @@ private void ensureMessageTypeIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.DescriptorProto, com.google.protobuf.DescriptorProtos.DescriptorProto.Builder, com.google.protobuf.DescriptorProtos.DescriptorProtoOrBuilder> messageTypeBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                DescriptorProto, DescriptorProto.Builder, DescriptorProtoOrBuilder> messageTypeBuilder_;
 
       /**
        * <pre>
@@ -3968,7 +3968,7 @@ public Builder addAllMessageType(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.DescriptorProto> values) {
         if (messageTypeBuilder_ == null) {
           ensureMessageTypeIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, messageType_);
           onChanged();
         } else {
@@ -4084,12 +4084,12 @@ public com.google.protobuf.DescriptorProtos.DescriptorProto.Builder addMessageTy
            getMessageTypeBuilderList() {
         return getMessageTypeFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.DescriptorProto, com.google.protobuf.DescriptorProtos.DescriptorProto.Builder, com.google.protobuf.DescriptorProtos.DescriptorProtoOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                DescriptorProto, DescriptorProto.Builder, DescriptorProtoOrBuilder>
           getMessageTypeFieldBuilder() {
         if (messageTypeBuilder_ == null) {
-          messageTypeBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.DescriptorProto, com.google.protobuf.DescriptorProtos.DescriptorProto.Builder, com.google.protobuf.DescriptorProtos.DescriptorProtoOrBuilder>(
+          messageTypeBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        DescriptorProto, DescriptorProto.Builder, DescriptorProtoOrBuilder>(
                   messageType_,
                   ((bitField0_ & 0x00000020) != 0),
                   getParentForChildren(),
@@ -4108,8 +4108,8 @@ private void ensureEnumTypeIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.EnumDescriptorProto, com.google.protobuf.DescriptorProtos.EnumDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.EnumDescriptorProtoOrBuilder> enumTypeBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                EnumDescriptorProto, EnumDescriptorProto.Builder, EnumDescriptorProtoOrBuilder> enumTypeBuilder_;
 
       /**
        * <code>repeated .google.protobuf.EnumDescriptorProto enum_type = 5;</code>
@@ -4240,7 +4240,7 @@ public Builder addAllEnumType(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.EnumDescriptorProto> values) {
         if (enumTypeBuilder_ == null) {
           ensureEnumTypeIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, enumType_);
           onChanged();
         } else {
@@ -4324,12 +4324,12 @@ public com.google.protobuf.DescriptorProtos.EnumDescriptorProto.Builder addEnumT
            getEnumTypeBuilderList() {
         return getEnumTypeFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.EnumDescriptorProto, com.google.protobuf.DescriptorProtos.EnumDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.EnumDescriptorProtoOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                EnumDescriptorProto, EnumDescriptorProto.Builder, EnumDescriptorProtoOrBuilder>
           getEnumTypeFieldBuilder() {
         if (enumTypeBuilder_ == null) {
-          enumTypeBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.EnumDescriptorProto, com.google.protobuf.DescriptorProtos.EnumDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.EnumDescriptorProtoOrBuilder>(
+          enumTypeBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        EnumDescriptorProto, EnumDescriptorProto.Builder, EnumDescriptorProtoOrBuilder>(
                   enumType_,
                   ((bitField0_ & 0x00000040) != 0),
                   getParentForChildren(),
@@ -4348,8 +4348,8 @@ private void ensureServiceIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.ServiceDescriptorProto, com.google.protobuf.DescriptorProtos.ServiceDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.ServiceDescriptorProtoOrBuilder> serviceBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                ServiceDescriptorProto, ServiceDescriptorProto.Builder, ServiceDescriptorProtoOrBuilder> serviceBuilder_;
 
       /**
        * <code>repeated .google.protobuf.ServiceDescriptorProto service = 6;</code>
@@ -4480,7 +4480,7 @@ public Builder addAllService(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.ServiceDescriptorProto> values) {
         if (serviceBuilder_ == null) {
           ensureServiceIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, service_);
           onChanged();
         } else {
@@ -4564,12 +4564,12 @@ public com.google.protobuf.DescriptorProtos.ServiceDescriptorProto.Builder addSe
            getServiceBuilderList() {
         return getServiceFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.ServiceDescriptorProto, com.google.protobuf.DescriptorProtos.ServiceDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.ServiceDescriptorProtoOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                ServiceDescriptorProto, ServiceDescriptorProto.Builder, ServiceDescriptorProtoOrBuilder>
           getServiceFieldBuilder() {
         if (serviceBuilder_ == null) {
-          serviceBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.ServiceDescriptorProto, com.google.protobuf.DescriptorProtos.ServiceDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.ServiceDescriptorProtoOrBuilder>(
+          serviceBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        ServiceDescriptorProto, ServiceDescriptorProto.Builder, ServiceDescriptorProtoOrBuilder>(
                   service_,
                   ((bitField0_ & 0x00000080) != 0),
                   getParentForChildren(),
@@ -4588,8 +4588,8 @@ private void ensureExtensionIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FieldDescriptorProto, com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.FieldDescriptorProtoOrBuilder> extensionBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                FieldDescriptorProto, FieldDescriptorProto.Builder, FieldDescriptorProtoOrBuilder> extensionBuilder_;
 
       /**
        * <code>repeated .google.protobuf.FieldDescriptorProto extension = 7;</code>
@@ -4720,7 +4720,7 @@ public Builder addAllExtension(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.FieldDescriptorProto> values) {
         if (extensionBuilder_ == null) {
           ensureExtensionIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, extension_);
           onChanged();
         } else {
@@ -4804,12 +4804,12 @@ public com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Builder addExte
            getExtensionBuilderList() {
         return getExtensionFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FieldDescriptorProto, com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.FieldDescriptorProtoOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                FieldDescriptorProto, FieldDescriptorProto.Builder, FieldDescriptorProtoOrBuilder>
           getExtensionFieldBuilder() {
         if (extensionBuilder_ == null) {
-          extensionBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.FieldDescriptorProto, com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.FieldDescriptorProtoOrBuilder>(
+          extensionBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        FieldDescriptorProto, FieldDescriptorProto.Builder, FieldDescriptorProtoOrBuilder>(
                   extension_,
                   ((bitField0_ & 0x00000100) != 0),
                   getParentForChildren(),
@@ -4820,8 +4820,8 @@ public com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Builder addExte
       }
 
       private com.google.protobuf.DescriptorProtos.FileOptions options_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FileOptions, com.google.protobuf.DescriptorProtos.FileOptions.Builder, com.google.protobuf.DescriptorProtos.FileOptionsOrBuilder> optionsBuilder_;
+      private SingleFieldBuilderV3Internal<
+                FileOptions, FileOptions.Builder, FileOptionsOrBuilder> optionsBuilder_;
       /**
        * <code>optional .google.protobuf.FileOptions options = 8;</code>
        * @return Whether the options field is set.
@@ -4926,12 +4926,12 @@ public com.google.protobuf.DescriptorProtos.FileOptionsOrBuilder getOptionsOrBui
       /**
        * <code>optional .google.protobuf.FileOptions options = 8;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FileOptions, com.google.protobuf.DescriptorProtos.FileOptions.Builder, com.google.protobuf.DescriptorProtos.FileOptionsOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                FileOptions, FileOptions.Builder, FileOptionsOrBuilder>
           getOptionsFieldBuilder() {
         if (optionsBuilder_ == null) {
-          optionsBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.FileOptions, com.google.protobuf.DescriptorProtos.FileOptions.Builder, com.google.protobuf.DescriptorProtos.FileOptionsOrBuilder>(
+          optionsBuilder_ = new SingleFieldBuilderV3Internal<
+                        FileOptions, FileOptions.Builder, FileOptionsOrBuilder>(
                   getOptions(),
                   getParentForChildren(),
                   isClean());
@@ -4941,8 +4941,8 @@ public com.google.protobuf.DescriptorProtos.FileOptionsOrBuilder getOptionsOrBui
       }
 
       private com.google.protobuf.DescriptorProtos.SourceCodeInfo sourceCodeInfo_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.SourceCodeInfo, com.google.protobuf.DescriptorProtos.SourceCodeInfo.Builder, com.google.protobuf.DescriptorProtos.SourceCodeInfoOrBuilder> sourceCodeInfoBuilder_;
+      private SingleFieldBuilderV3Internal<
+                SourceCodeInfo, SourceCodeInfo.Builder, SourceCodeInfoOrBuilder> sourceCodeInfoBuilder_;
       /**
        * <pre>
        * This field contains optional information about the original source code.
@@ -5110,12 +5110,12 @@ public com.google.protobuf.DescriptorProtos.SourceCodeInfoOrBuilder getSourceCod
        *
        * <code>optional .google.protobuf.SourceCodeInfo source_code_info = 9;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.SourceCodeInfo, com.google.protobuf.DescriptorProtos.SourceCodeInfo.Builder, com.google.protobuf.DescriptorProtos.SourceCodeInfoOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                SourceCodeInfo, SourceCodeInfo.Builder, SourceCodeInfoOrBuilder>
           getSourceCodeInfoFieldBuilder() {
         if (sourceCodeInfoBuilder_ == null) {
-          sourceCodeInfoBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.SourceCodeInfo, com.google.protobuf.DescriptorProtos.SourceCodeInfo.Builder, com.google.protobuf.DescriptorProtos.SourceCodeInfoOrBuilder>(
+          sourceCodeInfoBuilder_ = new SingleFieldBuilderV3Internal<
+                        SourceCodeInfo, SourceCodeInfo.Builder, SourceCodeInfoOrBuilder>(
                   getSourceCodeInfo(),
                   getParentForChildren(),
                   isClean());
@@ -5654,12 +5654,12 @@ com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRangeOrBuilder getR
    * Protobuf type {@code google.protobuf.DescriptorProto}
    */
   public static final class DescriptorProto extends
-      com.google.protobuf.GeneratedMessageV3 implements
+      com.google.protobuf.GeneratedMessageV3Internal implements
       // @@protoc_insertion_point(message_implements:google.protobuf.DescriptorProto)
       DescriptorProtoOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use DescriptorProto.newBuilder() to construct.
-    private DescriptorProto(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    private DescriptorProto(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
       super(builder);
     }
     private DescriptorProto() {
@@ -5688,7 +5688,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_DescriptorProto_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -5756,12 +5756,12 @@ public interface ExtensionRangeOrBuilder extends
      * Protobuf type {@code google.protobuf.DescriptorProto.ExtensionRange}
      */
     public static final class ExtensionRange extends
-        com.google.protobuf.GeneratedMessageV3 implements
+        com.google.protobuf.GeneratedMessageV3Internal implements
         // @@protoc_insertion_point(message_implements:google.protobuf.DescriptorProto.ExtensionRange)
         ExtensionRangeOrBuilder {
     private static final long serialVersionUID = 0L;
       // Use ExtensionRange.newBuilder() to construct.
-      private ExtensionRange(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+      private ExtensionRange(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
         super(builder);
       }
       private ExtensionRange() {
@@ -5780,7 +5780,7 @@ protected java.lang.Object newInstance(
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_DescriptorProto_ExtensionRange_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -6010,20 +6010,20 @@ public static com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRang
       }
       public static com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRange parseFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRange parseFrom(
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
       public static com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRange parseDelimitedFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input);
       }
 
@@ -6031,20 +6031,20 @@ public static com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRang
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
       }
       public static com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRange parseFrom(
           com.google.protobuf.CodedInputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRange parseFrom(
           com.google.protobuf.CodedInputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
@@ -6064,7 +6064,7 @@ public Builder toBuilder() {
 
       @java.lang.Override
       protected Builder newBuilderForType(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         Builder builder = new Builder(parent);
         return builder;
       }
@@ -6072,7 +6072,7 @@ protected Builder newBuilderForType(
        * Protobuf type {@code google.protobuf.DescriptorProto.ExtensionRange}
        */
       public static final class Builder extends
-          com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+          com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
           // @@protoc_insertion_point(builder_implements:google.protobuf.DescriptorProto.ExtensionRange)
           com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRangeOrBuilder {
         public static final com.google.protobuf.Descriptors.Descriptor
@@ -6081,7 +6081,7 @@ public static final class Builder extends
         }
 
         @java.lang.Override
-        protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
             internalGetFieldAccessorTable() {
           return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_DescriptorProto_ExtensionRange_fieldAccessorTable
               .ensureFieldAccessorsInitialized(
@@ -6094,12 +6094,12 @@ private Builder() {
         }
 
         private Builder(
-            com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+            com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
           super(parent);
           maybeForceBuilderInitialization();
         }
         private void maybeForceBuilderInitialization() {
-          if (com.google.protobuf.GeneratedMessageV3
+          if (com.google.protobuf.GeneratedMessageV3Internal
                   .alwaysUseFieldBuilders) {
             getOptionsFieldBuilder();
           }
@@ -6397,8 +6397,8 @@ public Builder clearEnd() {
         }
 
         private com.google.protobuf.DescriptorProtos.ExtensionRangeOptions options_;
-        private com.google.protobuf.SingleFieldBuilderV3<
-            com.google.protobuf.DescriptorProtos.ExtensionRangeOptions, com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.Builder, com.google.protobuf.DescriptorProtos.ExtensionRangeOptionsOrBuilder> optionsBuilder_;
+        private SingleFieldBuilderV3Internal<
+                    ExtensionRangeOptions, ExtensionRangeOptions.Builder, ExtensionRangeOptionsOrBuilder> optionsBuilder_;
         /**
          * <code>optional .google.protobuf.ExtensionRangeOptions options = 3;</code>
          * @return Whether the options field is set.
@@ -6503,12 +6503,12 @@ public com.google.protobuf.DescriptorProtos.ExtensionRangeOptionsOrBuilder getOp
         /**
          * <code>optional .google.protobuf.ExtensionRangeOptions options = 3;</code>
          */
-        private com.google.protobuf.SingleFieldBuilderV3<
-            com.google.protobuf.DescriptorProtos.ExtensionRangeOptions, com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.Builder, com.google.protobuf.DescriptorProtos.ExtensionRangeOptionsOrBuilder> 
+        private SingleFieldBuilderV3Internal<
+                    ExtensionRangeOptions, ExtensionRangeOptions.Builder, ExtensionRangeOptionsOrBuilder>
             getOptionsFieldBuilder() {
           if (optionsBuilder_ == null) {
-            optionsBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-                com.google.protobuf.DescriptorProtos.ExtensionRangeOptions, com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.Builder, com.google.protobuf.DescriptorProtos.ExtensionRangeOptionsOrBuilder>(
+            optionsBuilder_ = new SingleFieldBuilderV3Internal<
+                            ExtensionRangeOptions, ExtensionRangeOptions.Builder, ExtensionRangeOptionsOrBuilder>(
                     getOptions(),
                     getParentForChildren(),
                     isClean());
@@ -6632,12 +6632,12 @@ public interface ReservedRangeOrBuilder extends
      * Protobuf type {@code google.protobuf.DescriptorProto.ReservedRange}
      */
     public static final class ReservedRange extends
-        com.google.protobuf.GeneratedMessageV3 implements
+        com.google.protobuf.GeneratedMessageV3Internal implements
         // @@protoc_insertion_point(message_implements:google.protobuf.DescriptorProto.ReservedRange)
         ReservedRangeOrBuilder {
     private static final long serialVersionUID = 0L;
       // Use ReservedRange.newBuilder() to construct.
-      private ReservedRange(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+      private ReservedRange(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
         super(builder);
       }
       private ReservedRange() {
@@ -6656,7 +6656,7 @@ protected java.lang.Object newInstance(
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_DescriptorProto_ReservedRange_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -6838,20 +6838,20 @@ public static com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRange
       }
       public static com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRange parseFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRange parseFrom(
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
       public static com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRange parseDelimitedFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input);
       }
 
@@ -6859,20 +6859,20 @@ public static com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRange
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
       }
       public static com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRange parseFrom(
           com.google.protobuf.CodedInputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRange parseFrom(
           com.google.protobuf.CodedInputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
@@ -6892,7 +6892,7 @@ public Builder toBuilder() {
 
       @java.lang.Override
       protected Builder newBuilderForType(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         Builder builder = new Builder(parent);
         return builder;
       }
@@ -6906,7 +6906,7 @@ protected Builder newBuilderForType(
        * Protobuf type {@code google.protobuf.DescriptorProto.ReservedRange}
        */
       public static final class Builder extends
-          com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+          com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
           // @@protoc_insertion_point(builder_implements:google.protobuf.DescriptorProto.ReservedRange)
           com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRangeOrBuilder {
         public static final com.google.protobuf.Descriptors.Descriptor
@@ -6915,7 +6915,7 @@ public static final class Builder extends
         }
 
         @java.lang.Override
-        protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
             internalGetFieldAccessorTable() {
           return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_DescriptorProto_ReservedRange_fieldAccessorTable
               .ensureFieldAccessorsInitialized(
@@ -6928,7 +6928,7 @@ private Builder() {
         }
 
         private Builder(
-            com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+            com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
           super(parent);
 
         }
@@ -7738,7 +7738,7 @@ public final boolean isInitialized() {
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
       if (((bitField0_ & 0x00000001) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 1, name_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, name_);
       }
       for (int i = 0; i < field_.size(); i++) {
         output.writeMessage(2, field_.get(i));
@@ -7765,7 +7765,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output)
         output.writeMessage(9, reservedRange_.get(i));
       }
       for (int i = 0; i < reservedName_.size(); i++) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 10, reservedName_.getRaw(i));
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 10, reservedName_.getRaw(i));
       }
       getUnknownFields().writeTo(output);
     }
@@ -7777,7 +7777,7 @@ public int getSerializedSize() {
 
       size = 0;
       if (((bitField0_ & 0x00000001) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, name_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(1, name_);
       }
       for (int i = 0; i < field_.size(); i++) {
         size += com.google.protobuf.CodedOutputStream
@@ -7950,20 +7950,20 @@ public static com.google.protobuf.DescriptorProtos.DescriptorProto parseFrom(
     }
     public static com.google.protobuf.DescriptorProtos.DescriptorProto parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.DescriptorProto parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.DescriptorProto parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -7971,20 +7971,20 @@ public static com.google.protobuf.DescriptorProtos.DescriptorProto parseDelimite
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.DescriptorProto parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.DescriptorProto parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -8004,7 +8004,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -8016,7 +8016,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.DescriptorProto}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+        com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.DescriptorProto)
         com.google.protobuf.DescriptorProtos.DescriptorProtoOrBuilder {
       public static final com.google.protobuf.Descriptors.Descriptor
@@ -8025,7 +8025,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_DescriptorProto_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -8038,12 +8038,12 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
         maybeForceBuilderInitialization();
       }
       private void maybeForceBuilderInitialization() {
-        if (com.google.protobuf.GeneratedMessageV3
+        if (com.google.protobuf.GeneratedMessageV3Internal
                 .alwaysUseFieldBuilders) {
           getFieldFieldBuilder();
           getExtensionFieldBuilder();
@@ -8302,7 +8302,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.DescriptorProto ot
               field_ = other.field_;
               bitField0_ = (bitField0_ & ~0x00000002);
               fieldBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getFieldFieldBuilder() : null;
             } else {
               fieldBuilder_.addAllMessages(other.field_);
@@ -8328,7 +8328,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.DescriptorProto ot
               extension_ = other.extension_;
               bitField0_ = (bitField0_ & ~0x00000004);
               extensionBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getExtensionFieldBuilder() : null;
             } else {
               extensionBuilder_.addAllMessages(other.extension_);
@@ -8354,7 +8354,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.DescriptorProto ot
               nestedType_ = other.nestedType_;
               bitField0_ = (bitField0_ & ~0x00000008);
               nestedTypeBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getNestedTypeFieldBuilder() : null;
             } else {
               nestedTypeBuilder_.addAllMessages(other.nestedType_);
@@ -8380,7 +8380,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.DescriptorProto ot
               enumType_ = other.enumType_;
               bitField0_ = (bitField0_ & ~0x00000010);
               enumTypeBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getEnumTypeFieldBuilder() : null;
             } else {
               enumTypeBuilder_.addAllMessages(other.enumType_);
@@ -8406,7 +8406,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.DescriptorProto ot
               extensionRange_ = other.extensionRange_;
               bitField0_ = (bitField0_ & ~0x00000020);
               extensionRangeBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getExtensionRangeFieldBuilder() : null;
             } else {
               extensionRangeBuilder_.addAllMessages(other.extensionRange_);
@@ -8432,7 +8432,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.DescriptorProto ot
               oneofDecl_ = other.oneofDecl_;
               bitField0_ = (bitField0_ & ~0x00000040);
               oneofDeclBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getOneofDeclFieldBuilder() : null;
             } else {
               oneofDeclBuilder_.addAllMessages(other.oneofDecl_);
@@ -8461,7 +8461,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.DescriptorProto ot
               reservedRange_ = other.reservedRange_;
               bitField0_ = (bitField0_ & ~0x00000100);
               reservedRangeBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getReservedRangeFieldBuilder() : null;
             } else {
               reservedRangeBuilder_.addAllMessages(other.reservedRange_);
@@ -8754,8 +8754,8 @@ private void ensureFieldIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FieldDescriptorProto, com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.FieldDescriptorProtoOrBuilder> fieldBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                FieldDescriptorProto, FieldDescriptorProto.Builder, FieldDescriptorProtoOrBuilder> fieldBuilder_;
 
       /**
        * <code>repeated .google.protobuf.FieldDescriptorProto field = 2;</code>
@@ -8886,7 +8886,7 @@ public Builder addAllField(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.FieldDescriptorProto> values) {
         if (fieldBuilder_ == null) {
           ensureFieldIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, field_);
           onChanged();
         } else {
@@ -8970,12 +8970,12 @@ public com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Builder addFiel
            getFieldBuilderList() {
         return getFieldFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FieldDescriptorProto, com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.FieldDescriptorProtoOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                FieldDescriptorProto, FieldDescriptorProto.Builder, FieldDescriptorProtoOrBuilder>
           getFieldFieldBuilder() {
         if (fieldBuilder_ == null) {
-          fieldBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.FieldDescriptorProto, com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.FieldDescriptorProtoOrBuilder>(
+          fieldBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        FieldDescriptorProto, FieldDescriptorProto.Builder, FieldDescriptorProtoOrBuilder>(
                   field_,
                   ((bitField0_ & 0x00000002) != 0),
                   getParentForChildren(),
@@ -8994,8 +8994,8 @@ private void ensureExtensionIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FieldDescriptorProto, com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.FieldDescriptorProtoOrBuilder> extensionBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                FieldDescriptorProto, FieldDescriptorProto.Builder, FieldDescriptorProtoOrBuilder> extensionBuilder_;
 
       /**
        * <code>repeated .google.protobuf.FieldDescriptorProto extension = 6;</code>
@@ -9126,7 +9126,7 @@ public Builder addAllExtension(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.FieldDescriptorProto> values) {
         if (extensionBuilder_ == null) {
           ensureExtensionIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, extension_);
           onChanged();
         } else {
@@ -9210,12 +9210,12 @@ public com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Builder addExte
            getExtensionBuilderList() {
         return getExtensionFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FieldDescriptorProto, com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.FieldDescriptorProtoOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                FieldDescriptorProto, FieldDescriptorProto.Builder, FieldDescriptorProtoOrBuilder>
           getExtensionFieldBuilder() {
         if (extensionBuilder_ == null) {
-          extensionBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.FieldDescriptorProto, com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.FieldDescriptorProtoOrBuilder>(
+          extensionBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        FieldDescriptorProto, FieldDescriptorProto.Builder, FieldDescriptorProtoOrBuilder>(
                   extension_,
                   ((bitField0_ & 0x00000004) != 0),
                   getParentForChildren(),
@@ -9234,8 +9234,8 @@ private void ensureNestedTypeIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.DescriptorProto, com.google.protobuf.DescriptorProtos.DescriptorProto.Builder, com.google.protobuf.DescriptorProtos.DescriptorProtoOrBuilder> nestedTypeBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                DescriptorProto, Builder, DescriptorProtoOrBuilder> nestedTypeBuilder_;
 
       /**
        * <code>repeated .google.protobuf.DescriptorProto nested_type = 3;</code>
@@ -9366,7 +9366,7 @@ public Builder addAllNestedType(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.DescriptorProto> values) {
         if (nestedTypeBuilder_ == null) {
           ensureNestedTypeIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, nestedType_);
           onChanged();
         } else {
@@ -9450,12 +9450,12 @@ public com.google.protobuf.DescriptorProtos.DescriptorProto.Builder addNestedTyp
            getNestedTypeBuilderList() {
         return getNestedTypeFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.DescriptorProto, com.google.protobuf.DescriptorProtos.DescriptorProto.Builder, com.google.protobuf.DescriptorProtos.DescriptorProtoOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                DescriptorProto, Builder, DescriptorProtoOrBuilder>
           getNestedTypeFieldBuilder() {
         if (nestedTypeBuilder_ == null) {
-          nestedTypeBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.DescriptorProto, com.google.protobuf.DescriptorProtos.DescriptorProto.Builder, com.google.protobuf.DescriptorProtos.DescriptorProtoOrBuilder>(
+          nestedTypeBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        DescriptorProto, Builder, DescriptorProtoOrBuilder>(
                   nestedType_,
                   ((bitField0_ & 0x00000008) != 0),
                   getParentForChildren(),
@@ -9474,8 +9474,8 @@ private void ensureEnumTypeIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.EnumDescriptorProto, com.google.protobuf.DescriptorProtos.EnumDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.EnumDescriptorProtoOrBuilder> enumTypeBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                EnumDescriptorProto, EnumDescriptorProto.Builder, EnumDescriptorProtoOrBuilder> enumTypeBuilder_;
 
       /**
        * <code>repeated .google.protobuf.EnumDescriptorProto enum_type = 4;</code>
@@ -9606,7 +9606,7 @@ public Builder addAllEnumType(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.EnumDescriptorProto> values) {
         if (enumTypeBuilder_ == null) {
           ensureEnumTypeIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, enumType_);
           onChanged();
         } else {
@@ -9690,12 +9690,12 @@ public com.google.protobuf.DescriptorProtos.EnumDescriptorProto.Builder addEnumT
            getEnumTypeBuilderList() {
         return getEnumTypeFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.EnumDescriptorProto, com.google.protobuf.DescriptorProtos.EnumDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.EnumDescriptorProtoOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                EnumDescriptorProto, EnumDescriptorProto.Builder, EnumDescriptorProtoOrBuilder>
           getEnumTypeFieldBuilder() {
         if (enumTypeBuilder_ == null) {
-          enumTypeBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.EnumDescriptorProto, com.google.protobuf.DescriptorProtos.EnumDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.EnumDescriptorProtoOrBuilder>(
+          enumTypeBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        EnumDescriptorProto, EnumDescriptorProto.Builder, EnumDescriptorProtoOrBuilder>(
                   enumType_,
                   ((bitField0_ & 0x00000010) != 0),
                   getParentForChildren(),
@@ -9714,8 +9714,8 @@ private void ensureExtensionRangeIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRange, com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRange.Builder, com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRangeOrBuilder> extensionRangeBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                ExtensionRange, ExtensionRange.Builder, ExtensionRangeOrBuilder> extensionRangeBuilder_;
 
       /**
        * <code>repeated .google.protobuf.DescriptorProto.ExtensionRange extension_range = 5;</code>
@@ -9846,7 +9846,7 @@ public Builder addAllExtensionRange(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRange> values) {
         if (extensionRangeBuilder_ == null) {
           ensureExtensionRangeIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, extensionRange_);
           onChanged();
         } else {
@@ -9930,12 +9930,12 @@ public com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRange.Build
            getExtensionRangeBuilderList() {
         return getExtensionRangeFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRange, com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRange.Builder, com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRangeOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                ExtensionRange, ExtensionRange.Builder, ExtensionRangeOrBuilder>
           getExtensionRangeFieldBuilder() {
         if (extensionRangeBuilder_ == null) {
-          extensionRangeBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRange, com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRange.Builder, com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRangeOrBuilder>(
+          extensionRangeBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        ExtensionRange, ExtensionRange.Builder, ExtensionRangeOrBuilder>(
                   extensionRange_,
                   ((bitField0_ & 0x00000020) != 0),
                   getParentForChildren(),
@@ -9954,8 +9954,8 @@ private void ensureOneofDeclIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.OneofDescriptorProto, com.google.protobuf.DescriptorProtos.OneofDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.OneofDescriptorProtoOrBuilder> oneofDeclBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                OneofDescriptorProto, OneofDescriptorProto.Builder, OneofDescriptorProtoOrBuilder> oneofDeclBuilder_;
 
       /**
        * <code>repeated .google.protobuf.OneofDescriptorProto oneof_decl = 8;</code>
@@ -10086,7 +10086,7 @@ public Builder addAllOneofDecl(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.OneofDescriptorProto> values) {
         if (oneofDeclBuilder_ == null) {
           ensureOneofDeclIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, oneofDecl_);
           onChanged();
         } else {
@@ -10170,12 +10170,12 @@ public com.google.protobuf.DescriptorProtos.OneofDescriptorProto.Builder addOneo
            getOneofDeclBuilderList() {
         return getOneofDeclFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.OneofDescriptorProto, com.google.protobuf.DescriptorProtos.OneofDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.OneofDescriptorProtoOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                OneofDescriptorProto, OneofDescriptorProto.Builder, OneofDescriptorProtoOrBuilder>
           getOneofDeclFieldBuilder() {
         if (oneofDeclBuilder_ == null) {
-          oneofDeclBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.OneofDescriptorProto, com.google.protobuf.DescriptorProtos.OneofDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.OneofDescriptorProtoOrBuilder>(
+          oneofDeclBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        OneofDescriptorProto, OneofDescriptorProto.Builder, OneofDescriptorProtoOrBuilder>(
                   oneofDecl_,
                   ((bitField0_ & 0x00000040) != 0),
                   getParentForChildren(),
@@ -10186,8 +10186,8 @@ public com.google.protobuf.DescriptorProtos.OneofDescriptorProto.Builder addOneo
       }
 
       private com.google.protobuf.DescriptorProtos.MessageOptions options_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.MessageOptions, com.google.protobuf.DescriptorProtos.MessageOptions.Builder, com.google.protobuf.DescriptorProtos.MessageOptionsOrBuilder> optionsBuilder_;
+      private SingleFieldBuilderV3Internal<
+                MessageOptions, MessageOptions.Builder, MessageOptionsOrBuilder> optionsBuilder_;
       /**
        * <code>optional .google.protobuf.MessageOptions options = 7;</code>
        * @return Whether the options field is set.
@@ -10292,12 +10292,12 @@ public com.google.protobuf.DescriptorProtos.MessageOptionsOrBuilder getOptionsOr
       /**
        * <code>optional .google.protobuf.MessageOptions options = 7;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.MessageOptions, com.google.protobuf.DescriptorProtos.MessageOptions.Builder, com.google.protobuf.DescriptorProtos.MessageOptionsOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                MessageOptions, MessageOptions.Builder, MessageOptionsOrBuilder>
           getOptionsFieldBuilder() {
         if (optionsBuilder_ == null) {
-          optionsBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.MessageOptions, com.google.protobuf.DescriptorProtos.MessageOptions.Builder, com.google.protobuf.DescriptorProtos.MessageOptionsOrBuilder>(
+          optionsBuilder_ = new SingleFieldBuilderV3Internal<
+                        MessageOptions, MessageOptions.Builder, MessageOptionsOrBuilder>(
                   getOptions(),
                   getParentForChildren(),
                   isClean());
@@ -10315,8 +10315,8 @@ private void ensureReservedRangeIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRange, com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRange.Builder, com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRangeOrBuilder> reservedRangeBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                ReservedRange, ReservedRange.Builder, ReservedRangeOrBuilder> reservedRangeBuilder_;
 
       /**
        * <code>repeated .google.protobuf.DescriptorProto.ReservedRange reserved_range = 9;</code>
@@ -10447,7 +10447,7 @@ public Builder addAllReservedRange(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRange> values) {
         if (reservedRangeBuilder_ == null) {
           ensureReservedRangeIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, reservedRange_);
           onChanged();
         } else {
@@ -10531,12 +10531,12 @@ public com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRange.Builde
            getReservedRangeBuilderList() {
         return getReservedRangeFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRange, com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRange.Builder, com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRangeOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                ReservedRange, ReservedRange.Builder, ReservedRangeOrBuilder>
           getReservedRangeFieldBuilder() {
         if (reservedRangeBuilder_ == null) {
-          reservedRangeBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRange, com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRange.Builder, com.google.protobuf.DescriptorProtos.DescriptorProto.ReservedRangeOrBuilder>(
+          reservedRangeBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        ReservedRange, ReservedRange.Builder, ReservedRangeOrBuilder>(
                   reservedRange_,
                   ((bitField0_ & 0x00000100) != 0),
                   getParentForChildren(),
@@ -10659,7 +10659,7 @@ public Builder addReservedName(
       public Builder addAllReservedName(
           java.lang.Iterable<java.lang.String> values) {
         ensureReservedNameIsMutable();
-        com.google.protobuf.AbstractMessageLite.Builder.addAll(
+        com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
             values, reservedName_);
         bitField0_ |= 0x00000200;
         onChanged();
@@ -10766,7 +10766,7 @@ public com.google.protobuf.DescriptorProtos.DescriptorProto getDefaultInstanceFo
 
   public interface ExtensionRangeOptionsOrBuilder extends
       // @@protoc_insertion_point(interface_extends:google.protobuf.ExtensionRangeOptions)
-      com.google.protobuf.GeneratedMessageV3.
+      com.google.protobuf.GeneratedMessageV3Internal.
           ExtendableMessageOrBuilder<ExtensionRangeOptions> {
 
     /**
@@ -10921,13 +10921,13 @@ com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.DeclarationOrBuilder
    * Protobuf type {@code google.protobuf.ExtensionRangeOptions}
    */
   public static final class ExtensionRangeOptions extends
-      com.google.protobuf.GeneratedMessageV3.ExtendableMessage<
+      com.google.protobuf.GeneratedMessageV3Internal.ExtendableMessage<
         ExtensionRangeOptions> implements
       // @@protoc_insertion_point(message_implements:google.protobuf.ExtensionRangeOptions)
       ExtensionRangeOptionsOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use ExtensionRangeOptions.newBuilder() to construct.
-    private ExtensionRangeOptions(com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<com.google.protobuf.DescriptorProtos.ExtensionRangeOptions, ?> builder) {
+    private ExtensionRangeOptions(com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<com.google.protobuf.DescriptorProtos.ExtensionRangeOptions, ?> builder) {
       super(builder);
     }
     private ExtensionRangeOptions() {
@@ -10949,7 +10949,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_ExtensionRangeOptions_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -11202,12 +11202,12 @@ public interface DeclarationOrBuilder extends
      * Protobuf type {@code google.protobuf.ExtensionRangeOptions.Declaration}
      */
     public static final class Declaration extends
-        com.google.protobuf.GeneratedMessageV3 implements
+        com.google.protobuf.GeneratedMessageV3Internal implements
         // @@protoc_insertion_point(message_implements:google.protobuf.ExtensionRangeOptions.Declaration)
         DeclarationOrBuilder {
     private static final long serialVersionUID = 0L;
       // Use Declaration.newBuilder() to construct.
-      private Declaration(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+      private Declaration(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
         super(builder);
       }
       private Declaration() {
@@ -11228,7 +11228,7 @@ protected java.lang.Object newInstance(
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_ExtensionRangeOptions_Declaration_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -11472,10 +11472,10 @@ public void writeTo(com.google.protobuf.CodedOutputStream output)
           output.writeInt32(1, number_);
         }
         if (((bitField0_ & 0x00000002) != 0)) {
-          com.google.protobuf.GeneratedMessageV3.writeString(output, 2, fullName_);
+          com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 2, fullName_);
         }
         if (((bitField0_ & 0x00000004) != 0)) {
-          com.google.protobuf.GeneratedMessageV3.writeString(output, 3, type_);
+          com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 3, type_);
         }
         if (((bitField0_ & 0x00000008) != 0)) {
           output.writeBool(5, reserved_);
@@ -11497,10 +11497,10 @@ public int getSerializedSize() {
             .computeInt32Size(1, number_);
         }
         if (((bitField0_ & 0x00000002) != 0)) {
-          size += com.google.protobuf.GeneratedMessageV3.computeStringSize(2, fullName_);
+          size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(2, fullName_);
         }
         if (((bitField0_ & 0x00000004) != 0)) {
-          size += com.google.protobuf.GeneratedMessageV3.computeStringSize(3, type_);
+          size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(3, type_);
         }
         if (((bitField0_ & 0x00000008) != 0)) {
           size += com.google.protobuf.CodedOutputStream
@@ -11622,20 +11622,20 @@ public static com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.Declara
       }
       public static com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.Declaration parseFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.Declaration parseFrom(
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
       public static com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.Declaration parseDelimitedFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input);
       }
 
@@ -11643,20 +11643,20 @@ public static com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.Declara
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
       }
       public static com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.Declaration parseFrom(
           com.google.protobuf.CodedInputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.Declaration parseFrom(
           com.google.protobuf.CodedInputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
@@ -11676,7 +11676,7 @@ public Builder toBuilder() {
 
       @java.lang.Override
       protected Builder newBuilderForType(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         Builder builder = new Builder(parent);
         return builder;
       }
@@ -11684,7 +11684,7 @@ protected Builder newBuilderForType(
        * Protobuf type {@code google.protobuf.ExtensionRangeOptions.Declaration}
        */
       public static final class Builder extends
-          com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+          com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
           // @@protoc_insertion_point(builder_implements:google.protobuf.ExtensionRangeOptions.Declaration)
           com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.DeclarationOrBuilder {
         public static final com.google.protobuf.Descriptors.Descriptor
@@ -11693,7 +11693,7 @@ public static final class Builder extends
         }
 
         @java.lang.Override
-        protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
             internalGetFieldAccessorTable() {
           return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_ExtensionRangeOptions_Declaration_fieldAccessorTable
               .ensureFieldAccessorsInitialized(
@@ -11706,7 +11706,7 @@ private Builder() {
         }
 
         private Builder(
-            com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+            com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
           super(parent);
 
         }
@@ -12607,7 +12607,7 @@ public final boolean isInitialized() {
     @java.lang.Override
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
-      com.google.protobuf.GeneratedMessageV3
+      com.google.protobuf.GeneratedMessageV3Internal
         .ExtendableMessage<com.google.protobuf.DescriptorProtos.ExtensionRangeOptions>.ExtensionWriter
           extensionWriter = newExtensionWriter();
       for (int i = 0; i < declaration_.size(); i++) {
@@ -12746,20 +12746,20 @@ public static com.google.protobuf.DescriptorProtos.ExtensionRangeOptions parseFr
     }
     public static com.google.protobuf.DescriptorProtos.ExtensionRangeOptions parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.ExtensionRangeOptions parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.ExtensionRangeOptions parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -12767,20 +12767,20 @@ public static com.google.protobuf.DescriptorProtos.ExtensionRangeOptions parseDe
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.ExtensionRangeOptions parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.ExtensionRangeOptions parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -12800,7 +12800,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -12808,7 +12808,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.ExtensionRangeOptions}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<
+        com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<
           com.google.protobuf.DescriptorProtos.ExtensionRangeOptions, Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.ExtensionRangeOptions)
         com.google.protobuf.DescriptorProtos.ExtensionRangeOptionsOrBuilder {
@@ -12818,7 +12818,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_ExtensionRangeOptions_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -12831,12 +12831,12 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
         maybeForceBuilderInitialization();
       }
       private void maybeForceBuilderInitialization() {
-        if (com.google.protobuf.GeneratedMessageV3
+        if (com.google.protobuf.GeneratedMessageV3Internal
                 .alwaysUseFieldBuilders) {
           getUninterpretedOptionFieldBuilder();
           getDeclarationFieldBuilder();
@@ -12968,33 +12968,33 @@ public Builder addRepeatedField(
           java.lang.Object value) {
         return super.addRepeatedField(field, value);
       }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.ExtensionRangeOptions, Type> extension,
-          Type value) {
-        return super.setExtension(extension, value);
-      }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.ExtensionRangeOptions, java.util.List<Type>> extension,
-          int index, Type value) {
-        return super.setExtension(extension, index, value);
-      }
-      @java.lang.Override
-      public <Type> Builder addExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.ExtensionRangeOptions, java.util.List<Type>> extension,
-          Type value) {
-        return super.addExtension(extension, value);
-      }
-      @java.lang.Override
-      public <T> Builder clearExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.ExtensionRangeOptions, T> extension) {
-        return super.clearExtension(extension);
-      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.ExtensionRangeOptions, Type> extension,
+//          Type value) {
+//        return super.setExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.ExtensionRangeOptions, java.util.List<Type>> extension,
+//          int index, Type value) {
+//        return super.setExtension(extension, index, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder addExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.ExtensionRangeOptions, java.util.List<Type>> extension,
+//          Type value) {
+//        return super.addExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <T> Builder clearExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.ExtensionRangeOptions, T> extension) {
+//        return super.clearExtension(extension);
+//      }
       @java.lang.Override
       public Builder mergeFrom(com.google.protobuf.Message other) {
         if (other instanceof com.google.protobuf.DescriptorProtos.ExtensionRangeOptions) {
@@ -13026,7 +13026,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.ExtensionRangeOpti
               uninterpretedOption_ = other.uninterpretedOption_;
               bitField0_ = (bitField0_ & ~0x00000001);
               uninterpretedOptionBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getUninterpretedOptionFieldBuilder() : null;
             } else {
               uninterpretedOptionBuilder_.addAllMessages(other.uninterpretedOption_);
@@ -13052,7 +13052,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.ExtensionRangeOpti
               declaration_ = other.declaration_;
               bitField0_ = (bitField0_ & ~0x00000002);
               declarationBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getDeclarationFieldBuilder() : null;
             } else {
               declarationBuilder_.addAllMessages(other.declaration_);
@@ -13176,8 +13176,8 @@ private void ensureUninterpretedOptionIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder> uninterpretedOptionBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder> uninterpretedOptionBuilder_;
 
       /**
        * <pre>
@@ -13348,7 +13348,7 @@ public Builder addAllUninterpretedOption(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.UninterpretedOption> values) {
         if (uninterpretedOptionBuilder_ == null) {
           ensureUninterpretedOptionIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, uninterpretedOption_);
           onChanged();
         } else {
@@ -13464,12 +13464,12 @@ public com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder addUnint
            getUninterpretedOptionBuilderList() {
         return getUninterpretedOptionFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder>
           getUninterpretedOptionFieldBuilder() {
         if (uninterpretedOptionBuilder_ == null) {
-          uninterpretedOptionBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder>(
+          uninterpretedOptionBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder>(
                   uninterpretedOption_,
                   ((bitField0_ & 0x00000001) != 0),
                   getParentForChildren(),
@@ -13488,8 +13488,8 @@ private void ensureDeclarationIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.Declaration, com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.Declaration.Builder, com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.DeclarationOrBuilder> declarationBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                Declaration, Declaration.Builder, DeclarationOrBuilder> declarationBuilder_;
 
       /**
        * <pre>
@@ -13680,7 +13680,7 @@ public Builder addAllDeclaration(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.Declaration> values) {
         if (declarationBuilder_ == null) {
           ensureDeclarationIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, declaration_);
           onChanged();
         } else {
@@ -13812,12 +13812,12 @@ public com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.Declaration.Bu
            getDeclarationBuilderList() {
         return getDeclarationFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.Declaration, com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.Declaration.Builder, com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.DeclarationOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                Declaration, Declaration.Builder, DeclarationOrBuilder>
           getDeclarationFieldBuilder() {
         if (declarationBuilder_ == null) {
-          declarationBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.Declaration, com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.Declaration.Builder, com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.DeclarationOrBuilder>(
+          declarationBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        Declaration, Declaration.Builder, DeclarationOrBuilder>(
                   declaration_,
                   ((bitField0_ & 0x00000002) != 0),
                   getParentForChildren(),
@@ -13828,8 +13828,8 @@ public com.google.protobuf.DescriptorProtos.ExtensionRangeOptions.Declaration.Bu
       }
 
       private com.google.protobuf.DescriptorProtos.FeatureSet features_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> featuresBuilder_;
+      private SingleFieldBuilderV3Internal<
+                FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder> featuresBuilder_;
       /**
        * <pre>
        * Any features defined in the specific edition.
@@ -13970,12 +13970,12 @@ public com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder getFeaturesOrBui
        *
        * <code>optional .google.protobuf.FeatureSet features = 50;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>
           getFeaturesFieldBuilder() {
         if (featuresBuilder_ == null) {
-          featuresBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder>(
+          featuresBuilder_ = new SingleFieldBuilderV3Internal<
+                        FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>(
                   getFeatures(),
                   getParentForChildren(),
                   isClean());
@@ -14429,12 +14429,12 @@ public interface FieldDescriptorProtoOrBuilder extends
    * Protobuf type {@code google.protobuf.FieldDescriptorProto}
    */
   public static final class FieldDescriptorProto extends
-      com.google.protobuf.GeneratedMessageV3 implements
+      com.google.protobuf.GeneratedMessageV3Internal implements
       // @@protoc_insertion_point(message_implements:google.protobuf.FieldDescriptorProto)
       FieldDescriptorProtoOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use FieldDescriptorProto.newBuilder() to construct.
-    private FieldDescriptorProto(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    private FieldDescriptorProto(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
       super(builder);
     }
     private FieldDescriptorProto() {
@@ -14460,7 +14460,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FieldDescriptorProto_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -15445,10 +15445,10 @@ public final boolean isInitialized() {
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
       if (((bitField0_ & 0x00000001) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 1, name_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, name_);
       }
       if (((bitField0_ & 0x00000020) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 2, extendee_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 2, extendee_);
       }
       if (((bitField0_ & 0x00000002) != 0)) {
         output.writeInt32(3, number_);
@@ -15460,10 +15460,10 @@ public void writeTo(com.google.protobuf.CodedOutputStream output)
         output.writeEnum(5, type_);
       }
       if (((bitField0_ & 0x00000010) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 6, typeName_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 6, typeName_);
       }
       if (((bitField0_ & 0x00000040) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 7, defaultValue_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 7, defaultValue_);
       }
       if (((bitField0_ & 0x00000200) != 0)) {
         output.writeMessage(8, getOptions());
@@ -15472,7 +15472,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output)
         output.writeInt32(9, oneofIndex_);
       }
       if (((bitField0_ & 0x00000100) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 10, jsonName_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 10, jsonName_);
       }
       if (((bitField0_ & 0x00000400) != 0)) {
         output.writeBool(17, proto3Optional_);
@@ -15487,10 +15487,10 @@ public int getSerializedSize() {
 
       size = 0;
       if (((bitField0_ & 0x00000001) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, name_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(1, name_);
       }
       if (((bitField0_ & 0x00000020) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(2, extendee_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(2, extendee_);
       }
       if (((bitField0_ & 0x00000002) != 0)) {
         size += com.google.protobuf.CodedOutputStream
@@ -15505,10 +15505,10 @@ public int getSerializedSize() {
           .computeEnumSize(5, type_);
       }
       if (((bitField0_ & 0x00000010) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(6, typeName_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(6, typeName_);
       }
       if (((bitField0_ & 0x00000040) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(7, defaultValue_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(7, defaultValue_);
       }
       if (((bitField0_ & 0x00000200) != 0)) {
         size += com.google.protobuf.CodedOutputStream
@@ -15519,7 +15519,7 @@ public int getSerializedSize() {
           .computeInt32Size(9, oneofIndex_);
       }
       if (((bitField0_ & 0x00000100) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(10, jsonName_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(10, jsonName_);
       }
       if (((bitField0_ & 0x00000400) != 0)) {
         size += com.google.protobuf.CodedOutputStream
@@ -15688,20 +15688,20 @@ public static com.google.protobuf.DescriptorProtos.FieldDescriptorProto parseFro
     }
     public static com.google.protobuf.DescriptorProtos.FieldDescriptorProto parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.FieldDescriptorProto parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.FieldDescriptorProto parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -15709,20 +15709,20 @@ public static com.google.protobuf.DescriptorProtos.FieldDescriptorProto parseDel
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.FieldDescriptorProto parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.FieldDescriptorProto parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -15742,7 +15742,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -15754,7 +15754,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.FieldDescriptorProto}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+        com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.FieldDescriptorProto)
         com.google.protobuf.DescriptorProtos.FieldDescriptorProtoOrBuilder {
       public static final com.google.protobuf.Descriptors.Descriptor
@@ -15763,7 +15763,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FieldDescriptorProto_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -15776,12 +15776,12 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
         maybeForceBuilderInitialization();
       }
       private void maybeForceBuilderInitialization() {
-        if (com.google.protobuf.GeneratedMessageV3
+        if (com.google.protobuf.GeneratedMessageV3Internal
                 .alwaysUseFieldBuilders) {
           getOptionsFieldBuilder();
         }
@@ -16861,8 +16861,8 @@ public Builder setJsonNameBytes(
       }
 
       private com.google.protobuf.DescriptorProtos.FieldOptions options_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FieldOptions, com.google.protobuf.DescriptorProtos.FieldOptions.Builder, com.google.protobuf.DescriptorProtos.FieldOptionsOrBuilder> optionsBuilder_;
+      private SingleFieldBuilderV3Internal<
+                FieldOptions, FieldOptions.Builder, FieldOptionsOrBuilder> optionsBuilder_;
       /**
        * <code>optional .google.protobuf.FieldOptions options = 8;</code>
        * @return Whether the options field is set.
@@ -16967,12 +16967,12 @@ public com.google.protobuf.DescriptorProtos.FieldOptionsOrBuilder getOptionsOrBu
       /**
        * <code>optional .google.protobuf.FieldOptions options = 8;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FieldOptions, com.google.protobuf.DescriptorProtos.FieldOptions.Builder, com.google.protobuf.DescriptorProtos.FieldOptionsOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                FieldOptions, FieldOptions.Builder, FieldOptionsOrBuilder>
           getOptionsFieldBuilder() {
         if (optionsBuilder_ == null) {
-          optionsBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.FieldOptions, com.google.protobuf.DescriptorProtos.FieldOptions.Builder, com.google.protobuf.DescriptorProtos.FieldOptionsOrBuilder>(
+          optionsBuilder_ = new SingleFieldBuilderV3Internal<
+                        FieldOptions, FieldOptions.Builder, FieldOptionsOrBuilder>(
                   getOptions(),
                   getParentForChildren(),
                   isClean());
@@ -17224,12 +17224,12 @@ public interface OneofDescriptorProtoOrBuilder extends
    * Protobuf type {@code google.protobuf.OneofDescriptorProto}
    */
   public static final class OneofDescriptorProto extends
-      com.google.protobuf.GeneratedMessageV3 implements
+      com.google.protobuf.GeneratedMessageV3Internal implements
       // @@protoc_insertion_point(message_implements:google.protobuf.OneofDescriptorProto)
       OneofDescriptorProtoOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use OneofDescriptorProto.newBuilder() to construct.
-    private OneofDescriptorProto(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    private OneofDescriptorProto(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
       super(builder);
     }
     private OneofDescriptorProto() {
@@ -17249,7 +17249,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_OneofDescriptorProto_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -17353,7 +17353,7 @@ public final boolean isInitialized() {
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
       if (((bitField0_ & 0x00000001) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 1, name_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, name_);
       }
       if (((bitField0_ & 0x00000002) != 0)) {
         output.writeMessage(2, getOptions());
@@ -17368,7 +17368,7 @@ public int getSerializedSize() {
 
       size = 0;
       if (((bitField0_ & 0x00000001) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, name_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(1, name_);
       }
       if (((bitField0_ & 0x00000002) != 0)) {
         size += com.google.protobuf.CodedOutputStream
@@ -17457,20 +17457,20 @@ public static com.google.protobuf.DescriptorProtos.OneofDescriptorProto parseFro
     }
     public static com.google.protobuf.DescriptorProtos.OneofDescriptorProto parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.OneofDescriptorProto parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.OneofDescriptorProto parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -17478,20 +17478,20 @@ public static com.google.protobuf.DescriptorProtos.OneofDescriptorProto parseDel
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.OneofDescriptorProto parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.OneofDescriptorProto parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -17511,7 +17511,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -17523,7 +17523,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.OneofDescriptorProto}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+        com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.OneofDescriptorProto)
         com.google.protobuf.DescriptorProtos.OneofDescriptorProtoOrBuilder {
       public static final com.google.protobuf.Descriptors.Descriptor
@@ -17532,7 +17532,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_OneofDescriptorProto_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -17545,12 +17545,12 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
         maybeForceBuilderInitialization();
       }
       private void maybeForceBuilderInitialization() {
-        if (com.google.protobuf.GeneratedMessageV3
+        if (com.google.protobuf.GeneratedMessageV3Internal
                 .alwaysUseFieldBuilders) {
           getOptionsFieldBuilder();
         }
@@ -17805,8 +17805,8 @@ public Builder setNameBytes(
       }
 
       private com.google.protobuf.DescriptorProtos.OneofOptions options_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.OneofOptions, com.google.protobuf.DescriptorProtos.OneofOptions.Builder, com.google.protobuf.DescriptorProtos.OneofOptionsOrBuilder> optionsBuilder_;
+      private SingleFieldBuilderV3Internal<
+                OneofOptions, OneofOptions.Builder, OneofOptionsOrBuilder> optionsBuilder_;
       /**
        * <code>optional .google.protobuf.OneofOptions options = 2;</code>
        * @return Whether the options field is set.
@@ -17911,12 +17911,12 @@ public com.google.protobuf.DescriptorProtos.OneofOptionsOrBuilder getOptionsOrBu
       /**
        * <code>optional .google.protobuf.OneofOptions options = 2;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.OneofOptions, com.google.protobuf.DescriptorProtos.OneofOptions.Builder, com.google.protobuf.DescriptorProtos.OneofOptionsOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                OneofOptions, OneofOptions.Builder, OneofOptionsOrBuilder>
           getOptionsFieldBuilder() {
         if (optionsBuilder_ == null) {
-          optionsBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.OneofOptions, com.google.protobuf.DescriptorProtos.OneofOptions.Builder, com.google.protobuf.DescriptorProtos.OneofOptionsOrBuilder>(
+          optionsBuilder_ = new SingleFieldBuilderV3Internal<
+                        OneofOptions, OneofOptions.Builder, OneofOptionsOrBuilder>(
                   getOptions(),
                   getParentForChildren(),
                   isClean());
@@ -18155,12 +18155,12 @@ com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReservedRangeOrBuil
    * Protobuf type {@code google.protobuf.EnumDescriptorProto}
    */
   public static final class EnumDescriptorProto extends
-      com.google.protobuf.GeneratedMessageV3 implements
+      com.google.protobuf.GeneratedMessageV3Internal implements
       // @@protoc_insertion_point(message_implements:google.protobuf.EnumDescriptorProto)
       EnumDescriptorProtoOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use EnumDescriptorProto.newBuilder() to construct.
-    private EnumDescriptorProto(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    private EnumDescriptorProto(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
       super(builder);
     }
     private EnumDescriptorProto() {
@@ -18184,7 +18184,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_EnumDescriptorProto_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -18246,12 +18246,12 @@ public interface EnumReservedRangeOrBuilder extends
      * Protobuf type {@code google.protobuf.EnumDescriptorProto.EnumReservedRange}
      */
     public static final class EnumReservedRange extends
-        com.google.protobuf.GeneratedMessageV3 implements
+        com.google.protobuf.GeneratedMessageV3Internal implements
         // @@protoc_insertion_point(message_implements:google.protobuf.EnumDescriptorProto.EnumReservedRange)
         EnumReservedRangeOrBuilder {
     private static final long serialVersionUID = 0L;
       // Use EnumReservedRange.newBuilder() to construct.
-      private EnumReservedRange(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+      private EnumReservedRange(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
         super(builder);
       }
       private EnumReservedRange() {
@@ -18270,7 +18270,7 @@ protected java.lang.Object newInstance(
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_EnumDescriptorProto_EnumReservedRange_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -18452,20 +18452,20 @@ public static com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReser
       }
       public static com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReservedRange parseFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReservedRange parseFrom(
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
       public static com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReservedRange parseDelimitedFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input);
       }
 
@@ -18473,20 +18473,20 @@ public static com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReser
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
       }
       public static com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReservedRange parseFrom(
           com.google.protobuf.CodedInputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReservedRange parseFrom(
           com.google.protobuf.CodedInputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
@@ -18506,7 +18506,7 @@ public Builder toBuilder() {
 
       @java.lang.Override
       protected Builder newBuilderForType(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         Builder builder = new Builder(parent);
         return builder;
       }
@@ -18523,7 +18523,7 @@ protected Builder newBuilderForType(
        * Protobuf type {@code google.protobuf.EnumDescriptorProto.EnumReservedRange}
        */
       public static final class Builder extends
-          com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+          com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
           // @@protoc_insertion_point(builder_implements:google.protobuf.EnumDescriptorProto.EnumReservedRange)
           com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReservedRangeOrBuilder {
         public static final com.google.protobuf.Descriptors.Descriptor
@@ -18532,7 +18532,7 @@ public static final class Builder extends
         }
 
         @java.lang.Override
-        protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
             internalGetFieldAccessorTable() {
           return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_EnumDescriptorProto_EnumReservedRange_fieldAccessorTable
               .ensureFieldAccessorsInitialized(
@@ -18545,7 +18545,7 @@ private Builder() {
         }
 
         private Builder(
-            com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+            com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
           super(parent);
 
         }
@@ -19150,7 +19150,7 @@ public final boolean isInitialized() {
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
       if (((bitField0_ & 0x00000001) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 1, name_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, name_);
       }
       for (int i = 0; i < value_.size(); i++) {
         output.writeMessage(2, value_.get(i));
@@ -19162,7 +19162,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output)
         output.writeMessage(4, reservedRange_.get(i));
       }
       for (int i = 0; i < reservedName_.size(); i++) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 5, reservedName_.getRaw(i));
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 5, reservedName_.getRaw(i));
       }
       getUnknownFields().writeTo(output);
     }
@@ -19174,7 +19174,7 @@ public int getSerializedSize() {
 
       size = 0;
       if (((bitField0_ & 0x00000001) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, name_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(1, name_);
       }
       for (int i = 0; i < value_.size(); i++) {
         size += com.google.protobuf.CodedOutputStream
@@ -19297,20 +19297,20 @@ public static com.google.protobuf.DescriptorProtos.EnumDescriptorProto parseFrom
     }
     public static com.google.protobuf.DescriptorProtos.EnumDescriptorProto parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.EnumDescriptorProto parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.EnumDescriptorProto parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -19318,20 +19318,20 @@ public static com.google.protobuf.DescriptorProtos.EnumDescriptorProto parseDeli
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.EnumDescriptorProto parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.EnumDescriptorProto parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -19351,7 +19351,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -19363,7 +19363,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.EnumDescriptorProto}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+        com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.EnumDescriptorProto)
         com.google.protobuf.DescriptorProtos.EnumDescriptorProtoOrBuilder {
       public static final com.google.protobuf.Descriptors.Descriptor
@@ -19372,7 +19372,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_EnumDescriptorProto_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -19385,12 +19385,12 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
         maybeForceBuilderInitialization();
       }
       private void maybeForceBuilderInitialization() {
-        if (com.google.protobuf.GeneratedMessageV3
+        if (com.google.protobuf.GeneratedMessageV3Internal
                 .alwaysUseFieldBuilders) {
           getValueFieldBuilder();
           getOptionsFieldBuilder();
@@ -19564,7 +19564,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.EnumDescriptorProt
               value_ = other.value_;
               bitField0_ = (bitField0_ & ~0x00000002);
               valueBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getValueFieldBuilder() : null;
             } else {
               valueBuilder_.addAllMessages(other.value_);
@@ -19593,7 +19593,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.EnumDescriptorProt
               reservedRange_ = other.reservedRange_;
               bitField0_ = (bitField0_ & ~0x00000008);
               reservedRangeBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getReservedRangeFieldBuilder() : null;
             } else {
               reservedRangeBuilder_.addAllMessages(other.reservedRange_);
@@ -19796,8 +19796,8 @@ private void ensureValueIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.EnumValueDescriptorProto, com.google.protobuf.DescriptorProtos.EnumValueDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.EnumValueDescriptorProtoOrBuilder> valueBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                EnumValueDescriptorProto, EnumValueDescriptorProto.Builder, EnumValueDescriptorProtoOrBuilder> valueBuilder_;
 
       /**
        * <code>repeated .google.protobuf.EnumValueDescriptorProto value = 2;</code>
@@ -19928,7 +19928,7 @@ public Builder addAllValue(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.EnumValueDescriptorProto> values) {
         if (valueBuilder_ == null) {
           ensureValueIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, value_);
           onChanged();
         } else {
@@ -20012,12 +20012,12 @@ public com.google.protobuf.DescriptorProtos.EnumValueDescriptorProto.Builder add
            getValueBuilderList() {
         return getValueFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.EnumValueDescriptorProto, com.google.protobuf.DescriptorProtos.EnumValueDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.EnumValueDescriptorProtoOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                EnumValueDescriptorProto, EnumValueDescriptorProto.Builder, EnumValueDescriptorProtoOrBuilder>
           getValueFieldBuilder() {
         if (valueBuilder_ == null) {
-          valueBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.EnumValueDescriptorProto, com.google.protobuf.DescriptorProtos.EnumValueDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.EnumValueDescriptorProtoOrBuilder>(
+          valueBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        EnumValueDescriptorProto, EnumValueDescriptorProto.Builder, EnumValueDescriptorProtoOrBuilder>(
                   value_,
                   ((bitField0_ & 0x00000002) != 0),
                   getParentForChildren(),
@@ -20028,8 +20028,8 @@ public com.google.protobuf.DescriptorProtos.EnumValueDescriptorProto.Builder add
       }
 
       private com.google.protobuf.DescriptorProtos.EnumOptions options_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.EnumOptions, com.google.protobuf.DescriptorProtos.EnumOptions.Builder, com.google.protobuf.DescriptorProtos.EnumOptionsOrBuilder> optionsBuilder_;
+      private SingleFieldBuilderV3Internal<
+                EnumOptions, EnumOptions.Builder, EnumOptionsOrBuilder> optionsBuilder_;
       /**
        * <code>optional .google.protobuf.EnumOptions options = 3;</code>
        * @return Whether the options field is set.
@@ -20134,12 +20134,12 @@ public com.google.protobuf.DescriptorProtos.EnumOptionsOrBuilder getOptionsOrBui
       /**
        * <code>optional .google.protobuf.EnumOptions options = 3;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.EnumOptions, com.google.protobuf.DescriptorProtos.EnumOptions.Builder, com.google.protobuf.DescriptorProtos.EnumOptionsOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                EnumOptions, EnumOptions.Builder, EnumOptionsOrBuilder>
           getOptionsFieldBuilder() {
         if (optionsBuilder_ == null) {
-          optionsBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.EnumOptions, com.google.protobuf.DescriptorProtos.EnumOptions.Builder, com.google.protobuf.DescriptorProtos.EnumOptionsOrBuilder>(
+          optionsBuilder_ = new SingleFieldBuilderV3Internal<
+                        EnumOptions, EnumOptions.Builder, EnumOptionsOrBuilder>(
                   getOptions(),
                   getParentForChildren(),
                   isClean());
@@ -20157,8 +20157,8 @@ private void ensureReservedRangeIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReservedRange, com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReservedRange.Builder, com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReservedRangeOrBuilder> reservedRangeBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                EnumReservedRange, EnumReservedRange.Builder, EnumReservedRangeOrBuilder> reservedRangeBuilder_;
 
       /**
        * <pre>
@@ -20349,7 +20349,7 @@ public Builder addAllReservedRange(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReservedRange> values) {
         if (reservedRangeBuilder_ == null) {
           ensureReservedRangeIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, reservedRange_);
           onChanged();
         } else {
@@ -20481,12 +20481,12 @@ public com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReservedRang
            getReservedRangeBuilderList() {
         return getReservedRangeFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReservedRange, com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReservedRange.Builder, com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReservedRangeOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                EnumReservedRange, EnumReservedRange.Builder, EnumReservedRangeOrBuilder>
           getReservedRangeFieldBuilder() {
         if (reservedRangeBuilder_ == null) {
-          reservedRangeBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReservedRange, com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReservedRange.Builder, com.google.protobuf.DescriptorProtos.EnumDescriptorProto.EnumReservedRangeOrBuilder>(
+          reservedRangeBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        EnumReservedRange, EnumReservedRange.Builder, EnumReservedRangeOrBuilder>(
                   reservedRange_,
                   ((bitField0_ & 0x00000008) != 0),
                   getParentForChildren(),
@@ -20609,7 +20609,7 @@ public Builder addReservedName(
       public Builder addAllReservedName(
           java.lang.Iterable<java.lang.String> values) {
         ensureReservedNameIsMutable();
-        com.google.protobuf.AbstractMessageLite.Builder.addAll(
+        com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
             values, reservedName_);
         bitField0_ |= 0x00000010;
         onChanged();
@@ -20769,12 +20769,12 @@ public interface EnumValueDescriptorProtoOrBuilder extends
    * Protobuf type {@code google.protobuf.EnumValueDescriptorProto}
    */
   public static final class EnumValueDescriptorProto extends
-      com.google.protobuf.GeneratedMessageV3 implements
+      com.google.protobuf.GeneratedMessageV3Internal implements
       // @@protoc_insertion_point(message_implements:google.protobuf.EnumValueDescriptorProto)
       EnumValueDescriptorProtoOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use EnumValueDescriptorProto.newBuilder() to construct.
-    private EnumValueDescriptorProto(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    private EnumValueDescriptorProto(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
       super(builder);
     }
     private EnumValueDescriptorProto() {
@@ -20794,7 +20794,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_EnumValueDescriptorProto_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -20917,7 +20917,7 @@ public final boolean isInitialized() {
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
       if (((bitField0_ & 0x00000001) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 1, name_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, name_);
       }
       if (((bitField0_ & 0x00000002) != 0)) {
         output.writeInt32(2, number_);
@@ -20935,7 +20935,7 @@ public int getSerializedSize() {
 
       size = 0;
       if (((bitField0_ & 0x00000001) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, name_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(1, name_);
       }
       if (((bitField0_ & 0x00000002) != 0)) {
         size += com.google.protobuf.CodedOutputStream
@@ -21037,20 +21037,20 @@ public static com.google.protobuf.DescriptorProtos.EnumValueDescriptorProto pars
     }
     public static com.google.protobuf.DescriptorProtos.EnumValueDescriptorProto parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.EnumValueDescriptorProto parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.EnumValueDescriptorProto parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -21058,20 +21058,20 @@ public static com.google.protobuf.DescriptorProtos.EnumValueDescriptorProto pars
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.EnumValueDescriptorProto parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.EnumValueDescriptorProto parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -21091,7 +21091,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -21103,7 +21103,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.EnumValueDescriptorProto}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+        com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.EnumValueDescriptorProto)
         com.google.protobuf.DescriptorProtos.EnumValueDescriptorProtoOrBuilder {
       public static final com.google.protobuf.Descriptors.Descriptor
@@ -21112,7 +21112,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_EnumValueDescriptorProto_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -21125,12 +21125,12 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
         maybeForceBuilderInitialization();
       }
       private void maybeForceBuilderInitialization() {
-        if (com.google.protobuf.GeneratedMessageV3
+        if (com.google.protobuf.GeneratedMessageV3Internal
                 .alwaysUseFieldBuilders) {
           getOptionsFieldBuilder();
         }
@@ -21438,8 +21438,8 @@ public Builder clearNumber() {
       }
 
       private com.google.protobuf.DescriptorProtos.EnumValueOptions options_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.EnumValueOptions, com.google.protobuf.DescriptorProtos.EnumValueOptions.Builder, com.google.protobuf.DescriptorProtos.EnumValueOptionsOrBuilder> optionsBuilder_;
+      private SingleFieldBuilderV3Internal<
+                EnumValueOptions, EnumValueOptions.Builder, EnumValueOptionsOrBuilder> optionsBuilder_;
       /**
        * <code>optional .google.protobuf.EnumValueOptions options = 3;</code>
        * @return Whether the options field is set.
@@ -21544,12 +21544,12 @@ public com.google.protobuf.DescriptorProtos.EnumValueOptionsOrBuilder getOptions
       /**
        * <code>optional .google.protobuf.EnumValueOptions options = 3;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.EnumValueOptions, com.google.protobuf.DescriptorProtos.EnumValueOptions.Builder, com.google.protobuf.DescriptorProtos.EnumValueOptionsOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                EnumValueOptions, EnumValueOptions.Builder, EnumValueOptionsOrBuilder>
           getOptionsFieldBuilder() {
         if (optionsBuilder_ == null) {
-          optionsBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.EnumValueOptions, com.google.protobuf.DescriptorProtos.EnumValueOptions.Builder, com.google.protobuf.DescriptorProtos.EnumValueOptionsOrBuilder>(
+          optionsBuilder_ = new SingleFieldBuilderV3Internal<
+                        EnumValueOptions, EnumValueOptions.Builder, EnumValueOptionsOrBuilder>(
                   getOptions(),
                   getParentForChildren(),
                   isClean());
@@ -21689,12 +21689,12 @@ com.google.protobuf.DescriptorProtos.MethodDescriptorProtoOrBuilder getMethodOrB
    * Protobuf type {@code google.protobuf.ServiceDescriptorProto}
    */
   public static final class ServiceDescriptorProto extends
-      com.google.protobuf.GeneratedMessageV3 implements
+      com.google.protobuf.GeneratedMessageV3Internal implements
       // @@protoc_insertion_point(message_implements:google.protobuf.ServiceDescriptorProto)
       ServiceDescriptorProtoOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use ServiceDescriptorProto.newBuilder() to construct.
-    private ServiceDescriptorProto(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    private ServiceDescriptorProto(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
       super(builder);
     }
     private ServiceDescriptorProto() {
@@ -21715,7 +21715,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_ServiceDescriptorProto_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -21866,7 +21866,7 @@ public final boolean isInitialized() {
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
       if (((bitField0_ & 0x00000001) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 1, name_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, name_);
       }
       for (int i = 0; i < method_.size(); i++) {
         output.writeMessage(2, method_.get(i));
@@ -21884,7 +21884,7 @@ public int getSerializedSize() {
 
       size = 0;
       if (((bitField0_ & 0x00000001) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, name_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(1, name_);
       }
       for (int i = 0; i < method_.size(); i++) {
         size += com.google.protobuf.CodedOutputStream
@@ -21983,20 +21983,20 @@ public static com.google.protobuf.DescriptorProtos.ServiceDescriptorProto parseF
     }
     public static com.google.protobuf.DescriptorProtos.ServiceDescriptorProto parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.ServiceDescriptorProto parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.ServiceDescriptorProto parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -22004,20 +22004,20 @@ public static com.google.protobuf.DescriptorProtos.ServiceDescriptorProto parseD
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.ServiceDescriptorProto parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.ServiceDescriptorProto parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -22037,7 +22037,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -22049,7 +22049,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.ServiceDescriptorProto}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+        com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.ServiceDescriptorProto)
         com.google.protobuf.DescriptorProtos.ServiceDescriptorProtoOrBuilder {
       public static final com.google.protobuf.Descriptors.Descriptor
@@ -22058,7 +22058,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_ServiceDescriptorProto_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -22071,12 +22071,12 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
         maybeForceBuilderInitialization();
       }
       private void maybeForceBuilderInitialization() {
-        if (com.google.protobuf.GeneratedMessageV3
+        if (com.google.protobuf.GeneratedMessageV3Internal
                 .alwaysUseFieldBuilders) {
           getMethodFieldBuilder();
           getOptionsFieldBuilder();
@@ -22227,7 +22227,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.ServiceDescriptorP
               method_ = other.method_;
               bitField0_ = (bitField0_ & ~0x00000002);
               methodBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getMethodFieldBuilder() : null;
             } else {
               methodBuilder_.addAllMessages(other.method_);
@@ -22404,8 +22404,8 @@ private void ensureMethodIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.MethodDescriptorProto, com.google.protobuf.DescriptorProtos.MethodDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.MethodDescriptorProtoOrBuilder> methodBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                MethodDescriptorProto, MethodDescriptorProto.Builder, MethodDescriptorProtoOrBuilder> methodBuilder_;
 
       /**
        * <code>repeated .google.protobuf.MethodDescriptorProto method = 2;</code>
@@ -22536,7 +22536,7 @@ public Builder addAllMethod(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.MethodDescriptorProto> values) {
         if (methodBuilder_ == null) {
           ensureMethodIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, method_);
           onChanged();
         } else {
@@ -22620,12 +22620,12 @@ public com.google.protobuf.DescriptorProtos.MethodDescriptorProto.Builder addMet
            getMethodBuilderList() {
         return getMethodFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.MethodDescriptorProto, com.google.protobuf.DescriptorProtos.MethodDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.MethodDescriptorProtoOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                MethodDescriptorProto, MethodDescriptorProto.Builder, MethodDescriptorProtoOrBuilder>
           getMethodFieldBuilder() {
         if (methodBuilder_ == null) {
-          methodBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.MethodDescriptorProto, com.google.protobuf.DescriptorProtos.MethodDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.MethodDescriptorProtoOrBuilder>(
+          methodBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        MethodDescriptorProto, MethodDescriptorProto.Builder, MethodDescriptorProtoOrBuilder>(
                   method_,
                   ((bitField0_ & 0x00000002) != 0),
                   getParentForChildren(),
@@ -22636,8 +22636,8 @@ public com.google.protobuf.DescriptorProtos.MethodDescriptorProto.Builder addMet
       }
 
       private com.google.protobuf.DescriptorProtos.ServiceOptions options_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.ServiceOptions, com.google.protobuf.DescriptorProtos.ServiceOptions.Builder, com.google.protobuf.DescriptorProtos.ServiceOptionsOrBuilder> optionsBuilder_;
+      private SingleFieldBuilderV3Internal<
+                ServiceOptions, ServiceOptions.Builder, ServiceOptionsOrBuilder> optionsBuilder_;
       /**
        * <code>optional .google.protobuf.ServiceOptions options = 3;</code>
        * @return Whether the options field is set.
@@ -22742,12 +22742,12 @@ public com.google.protobuf.DescriptorProtos.ServiceOptionsOrBuilder getOptionsOr
       /**
        * <code>optional .google.protobuf.ServiceOptions options = 3;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.ServiceOptions, com.google.protobuf.DescriptorProtos.ServiceOptions.Builder, com.google.protobuf.DescriptorProtos.ServiceOptionsOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                ServiceOptions, ServiceOptions.Builder, ServiceOptionsOrBuilder>
           getOptionsFieldBuilder() {
         if (optionsBuilder_ == null) {
-          optionsBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.ServiceOptions, com.google.protobuf.DescriptorProtos.ServiceOptions.Builder, com.google.protobuf.DescriptorProtos.ServiceOptionsOrBuilder>(
+          optionsBuilder_ = new SingleFieldBuilderV3Internal<
+                        ServiceOptions, ServiceOptions.Builder, ServiceOptionsOrBuilder>(
                   getOptions(),
                   getParentForChildren(),
                   isClean());
@@ -22950,12 +22950,12 @@ public interface MethodDescriptorProtoOrBuilder extends
    * Protobuf type {@code google.protobuf.MethodDescriptorProto}
    */
   public static final class MethodDescriptorProto extends
-      com.google.protobuf.GeneratedMessageV3 implements
+      com.google.protobuf.GeneratedMessageV3Internal implements
       // @@protoc_insertion_point(message_implements:google.protobuf.MethodDescriptorProto)
       MethodDescriptorProtoOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use MethodDescriptorProto.newBuilder() to construct.
-    private MethodDescriptorProto(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    private MethodDescriptorProto(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
       super(builder);
     }
     private MethodDescriptorProto() {
@@ -22977,7 +22977,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_MethodDescriptorProto_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -23248,13 +23248,13 @@ public final boolean isInitialized() {
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
       if (((bitField0_ & 0x00000001) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 1, name_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, name_);
       }
       if (((bitField0_ & 0x00000002) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 2, inputType_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 2, inputType_);
       }
       if (((bitField0_ & 0x00000004) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 3, outputType_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 3, outputType_);
       }
       if (((bitField0_ & 0x00000008) != 0)) {
         output.writeMessage(4, getOptions());
@@ -23275,13 +23275,13 @@ public int getSerializedSize() {
 
       size = 0;
       if (((bitField0_ & 0x00000001) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, name_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(1, name_);
       }
       if (((bitField0_ & 0x00000002) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(2, inputType_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(2, inputType_);
       }
       if (((bitField0_ & 0x00000004) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(3, outputType_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(3, outputType_);
       }
       if (((bitField0_ & 0x00000008) != 0)) {
         size += com.google.protobuf.CodedOutputStream
@@ -23416,20 +23416,20 @@ public static com.google.protobuf.DescriptorProtos.MethodDescriptorProto parseFr
     }
     public static com.google.protobuf.DescriptorProtos.MethodDescriptorProto parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.MethodDescriptorProto parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.MethodDescriptorProto parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -23437,20 +23437,20 @@ public static com.google.protobuf.DescriptorProtos.MethodDescriptorProto parseDe
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.MethodDescriptorProto parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.MethodDescriptorProto parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -23470,7 +23470,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -23482,7 +23482,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.MethodDescriptorProto}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+        com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.MethodDescriptorProto)
         com.google.protobuf.DescriptorProtos.MethodDescriptorProtoOrBuilder {
       public static final com.google.protobuf.Descriptors.Descriptor
@@ -23491,7 +23491,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_MethodDescriptorProto_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -23504,12 +23504,12 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
         maybeForceBuilderInitialization();
       }
       private void maybeForceBuilderInitialization() {
-        if (com.google.protobuf.GeneratedMessageV3
+        if (com.google.protobuf.GeneratedMessageV3Internal
                 .alwaysUseFieldBuilders) {
           getOptionsFieldBuilder();
         }
@@ -24010,8 +24010,8 @@ public Builder setOutputTypeBytes(
       }
 
       private com.google.protobuf.DescriptorProtos.MethodOptions options_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.MethodOptions, com.google.protobuf.DescriptorProtos.MethodOptions.Builder, com.google.protobuf.DescriptorProtos.MethodOptionsOrBuilder> optionsBuilder_;
+      private SingleFieldBuilderV3Internal<
+                MethodOptions, MethodOptions.Builder, MethodOptionsOrBuilder> optionsBuilder_;
       /**
        * <code>optional .google.protobuf.MethodOptions options = 4;</code>
        * @return Whether the options field is set.
@@ -24116,12 +24116,12 @@ public com.google.protobuf.DescriptorProtos.MethodOptionsOrBuilder getOptionsOrB
       /**
        * <code>optional .google.protobuf.MethodOptions options = 4;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.MethodOptions, com.google.protobuf.DescriptorProtos.MethodOptions.Builder, com.google.protobuf.DescriptorProtos.MethodOptionsOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                MethodOptions, MethodOptions.Builder, MethodOptionsOrBuilder>
           getOptionsFieldBuilder() {
         if (optionsBuilder_ == null) {
-          optionsBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.MethodOptions, com.google.protobuf.DescriptorProtos.MethodOptions.Builder, com.google.protobuf.DescriptorProtos.MethodOptionsOrBuilder>(
+          optionsBuilder_ = new SingleFieldBuilderV3Internal<
+                        MethodOptions, MethodOptions.Builder, MethodOptionsOrBuilder>(
                   getOptions(),
                   getParentForChildren(),
                   isClean());
@@ -24307,7 +24307,7 @@ public com.google.protobuf.DescriptorProtos.MethodDescriptorProto getDefaultInst
 
   public interface FileOptionsOrBuilder extends
       // @@protoc_insertion_point(interface_extends:google.protobuf.FileOptions)
-      com.google.protobuf.GeneratedMessageV3.
+      com.google.protobuf.GeneratedMessageV3Internal.
           ExtendableMessageOrBuilder<FileOptions> {
 
     /**
@@ -24960,13 +24960,13 @@ com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder getUninterpret
    * Protobuf type {@code google.protobuf.FileOptions}
    */
   public static final class FileOptions extends
-      com.google.protobuf.GeneratedMessageV3.ExtendableMessage<
+      com.google.protobuf.GeneratedMessageV3Internal.ExtendableMessage<
         FileOptions> implements
       // @@protoc_insertion_point(message_implements:google.protobuf.FileOptions)
       FileOptionsOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use FileOptions.newBuilder() to construct.
-    private FileOptions(com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<com.google.protobuf.DescriptorProtos.FileOptions, ?> builder) {
+    private FileOptions(com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<com.google.protobuf.DescriptorProtos.FileOptions, ?> builder) {
       super(builder);
     }
     private FileOptions() {
@@ -24998,7 +24998,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FileOptions_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -26234,14 +26234,14 @@ public final boolean isInitialized() {
     @java.lang.Override
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
-      com.google.protobuf.GeneratedMessageV3
+      com.google.protobuf.GeneratedMessageV3Internal
         .ExtendableMessage<com.google.protobuf.DescriptorProtos.FileOptions>.ExtensionWriter
           extensionWriter = newExtensionWriter();
       if (((bitField0_ & 0x00000001) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 1, javaPackage_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, javaPackage_);
       }
       if (((bitField0_ & 0x00000002) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 8, javaOuterClassname_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 8, javaOuterClassname_);
       }
       if (((bitField0_ & 0x00000020) != 0)) {
         output.writeEnum(9, optimizeFor_);
@@ -26250,7 +26250,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output)
         output.writeBool(10, javaMultipleFiles_);
       }
       if (((bitField0_ & 0x00000040) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 11, goPackage_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 11, goPackage_);
       }
       if (((bitField0_ & 0x00000080) != 0)) {
         output.writeBool(16, ccGenericServices_);
@@ -26274,25 +26274,25 @@ public void writeTo(com.google.protobuf.CodedOutputStream output)
         output.writeBool(31, ccEnableArenas_);
       }
       if (((bitField0_ & 0x00001000) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 36, objcClassPrefix_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 36, objcClassPrefix_);
       }
       if (((bitField0_ & 0x00002000) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 37, csharpNamespace_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 37, csharpNamespace_);
       }
       if (((bitField0_ & 0x00004000) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 39, swiftPrefix_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 39, swiftPrefix_);
       }
       if (((bitField0_ & 0x00008000) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 40, phpClassPrefix_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 40, phpClassPrefix_);
       }
       if (((bitField0_ & 0x00010000) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 41, phpNamespace_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 41, phpNamespace_);
       }
       if (((bitField0_ & 0x00020000) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 44, phpMetadataNamespace_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 44, phpMetadataNamespace_);
       }
       if (((bitField0_ & 0x00040000) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 45, rubyPackage_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 45, rubyPackage_);
       }
       if (((bitField0_ & 0x00080000) != 0)) {
         output.writeMessage(50, getFeatures());
@@ -26311,10 +26311,10 @@ public int getSerializedSize() {
 
       size = 0;
       if (((bitField0_ & 0x00000001) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, javaPackage_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(1, javaPackage_);
       }
       if (((bitField0_ & 0x00000002) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(8, javaOuterClassname_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(8, javaOuterClassname_);
       }
       if (((bitField0_ & 0x00000020) != 0)) {
         size += com.google.protobuf.CodedOutputStream
@@ -26325,7 +26325,7 @@ public int getSerializedSize() {
           .computeBoolSize(10, javaMultipleFiles_);
       }
       if (((bitField0_ & 0x00000040) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(11, goPackage_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(11, goPackage_);
       }
       if (((bitField0_ & 0x00000080) != 0)) {
         size += com.google.protobuf.CodedOutputStream
@@ -26356,25 +26356,25 @@ public int getSerializedSize() {
           .computeBoolSize(31, ccEnableArenas_);
       }
       if (((bitField0_ & 0x00001000) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(36, objcClassPrefix_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(36, objcClassPrefix_);
       }
       if (((bitField0_ & 0x00002000) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(37, csharpNamespace_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(37, csharpNamespace_);
       }
       if (((bitField0_ & 0x00004000) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(39, swiftPrefix_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(39, swiftPrefix_);
       }
       if (((bitField0_ & 0x00008000) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(40, phpClassPrefix_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(40, phpClassPrefix_);
       }
       if (((bitField0_ & 0x00010000) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(41, phpNamespace_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(41, phpNamespace_);
       }
       if (((bitField0_ & 0x00020000) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(44, phpMetadataNamespace_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(44, phpMetadataNamespace_);
       }
       if (((bitField0_ & 0x00040000) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(45, rubyPackage_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(45, rubyPackage_);
       }
       if (((bitField0_ & 0x00080000) != 0)) {
         size += com.google.protobuf.CodedOutputStream
@@ -26646,20 +26646,20 @@ public static com.google.protobuf.DescriptorProtos.FileOptions parseFrom(
     }
     public static com.google.protobuf.DescriptorProtos.FileOptions parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.FileOptions parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.FileOptions parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -26667,20 +26667,20 @@ public static com.google.protobuf.DescriptorProtos.FileOptions parseDelimitedFro
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.FileOptions parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.FileOptions parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -26700,7 +26700,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -26708,7 +26708,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.FileOptions}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<
+        com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<
           com.google.protobuf.DescriptorProtos.FileOptions, Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.FileOptions)
         com.google.protobuf.DescriptorProtos.FileOptionsOrBuilder {
@@ -26718,7 +26718,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FileOptions_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -26731,12 +26731,12 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
         maybeForceBuilderInitialization();
       }
       private void maybeForceBuilderInitialization() {
-        if (com.google.protobuf.GeneratedMessageV3
+        if (com.google.protobuf.GeneratedMessageV3Internal
                 .alwaysUseFieldBuilders) {
           getFeaturesFieldBuilder();
           getUninterpretedOptionFieldBuilder();
@@ -26941,33 +26941,33 @@ public Builder addRepeatedField(
           java.lang.Object value) {
         return super.addRepeatedField(field, value);
       }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.FileOptions, Type> extension,
-          Type value) {
-        return super.setExtension(extension, value);
-      }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.FileOptions, java.util.List<Type>> extension,
-          int index, Type value) {
-        return super.setExtension(extension, index, value);
-      }
-      @java.lang.Override
-      public <Type> Builder addExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.FileOptions, java.util.List<Type>> extension,
-          Type value) {
-        return super.addExtension(extension, value);
-      }
-      @java.lang.Override
-      public <T> Builder clearExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.FileOptions, T> extension) {
-        return super.clearExtension(extension);
-      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.FileOptions, Type> extension,
+//          Type value) {
+//        return super.setExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.FileOptions, java.util.List<Type>> extension,
+//          int index, Type value) {
+//        return super.setExtension(extension, index, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder addExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.FileOptions, java.util.List<Type>> extension,
+//          Type value) {
+//        return super.addExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <T> Builder clearExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.FileOptions, T> extension) {
+//        return super.clearExtension(extension);
+//      }
       @java.lang.Override
       public Builder mergeFrom(com.google.protobuf.Message other) {
         if (other instanceof com.google.protobuf.DescriptorProtos.FileOptions) {
@@ -27079,7 +27079,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.FileOptions other)
               uninterpretedOption_ = other.uninterpretedOption_;
               bitField0_ = (bitField0_ & ~0x00100000);
               uninterpretedOptionBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getUninterpretedOptionFieldBuilder() : null;
             } else {
               uninterpretedOptionBuilder_.addAllMessages(other.uninterpretedOption_);
@@ -29012,8 +29012,8 @@ public Builder setRubyPackageBytes(
       }
 
       private com.google.protobuf.DescriptorProtos.FeatureSet features_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> featuresBuilder_;
+      private SingleFieldBuilderV3Internal<
+                FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder> featuresBuilder_;
       /**
        * <pre>
        * Any features defined in the specific edition.
@@ -29181,12 +29181,12 @@ public com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder getFeaturesOrBui
        *
        * <code>optional .google.protobuf.FeatureSet features = 50;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>
           getFeaturesFieldBuilder() {
         if (featuresBuilder_ == null) {
-          featuresBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder>(
+          featuresBuilder_ = new SingleFieldBuilderV3Internal<
+                        FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>(
                   getFeatures(),
                   getParentForChildren(),
                   isClean());
@@ -29204,8 +29204,8 @@ private void ensureUninterpretedOptionIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder> uninterpretedOptionBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder> uninterpretedOptionBuilder_;
 
       /**
        * <pre>
@@ -29386,7 +29386,7 @@ public Builder addAllUninterpretedOption(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.UninterpretedOption> values) {
         if (uninterpretedOptionBuilder_ == null) {
           ensureUninterpretedOptionIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, uninterpretedOption_);
           onChanged();
         } else {
@@ -29510,12 +29510,12 @@ public com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder addUnint
            getUninterpretedOptionBuilderList() {
         return getUninterpretedOptionFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder>
           getUninterpretedOptionFieldBuilder() {
         if (uninterpretedOptionBuilder_ == null) {
-          uninterpretedOptionBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder>(
+          uninterpretedOptionBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder>(
                   uninterpretedOption_,
                   ((bitField0_ & 0x00100000) != 0),
                   getParentForChildren(),
@@ -29590,7 +29590,7 @@ public com.google.protobuf.DescriptorProtos.FileOptions getDefaultInstanceForTyp
 
   public interface MessageOptionsOrBuilder extends
       // @@protoc_insertion_point(interface_extends:google.protobuf.MessageOptions)
-      com.google.protobuf.GeneratedMessageV3.
+      com.google.protobuf.GeneratedMessageV3Internal.
           ExtendableMessageOrBuilder<MessageOptions> {
 
     /**
@@ -29878,13 +29878,13 @@ com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder getUninterpret
    * Protobuf type {@code google.protobuf.MessageOptions}
    */
   public static final class MessageOptions extends
-      com.google.protobuf.GeneratedMessageV3.ExtendableMessage<
+      com.google.protobuf.GeneratedMessageV3Internal.ExtendableMessage<
         MessageOptions> implements
       // @@protoc_insertion_point(message_implements:google.protobuf.MessageOptions)
       MessageOptionsOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use MessageOptions.newBuilder() to construct.
-    private MessageOptions(com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<com.google.protobuf.DescriptorProtos.MessageOptions, ?> builder) {
+    private MessageOptions(com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<com.google.protobuf.DescriptorProtos.MessageOptions, ?> builder) {
       super(builder);
     }
     private MessageOptions() {
@@ -29904,7 +29904,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_MessageOptions_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -30291,7 +30291,7 @@ public final boolean isInitialized() {
     @java.lang.Override
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
-      com.google.protobuf.GeneratedMessageV3
+      com.google.protobuf.GeneratedMessageV3Internal
         .ExtendableMessage<com.google.protobuf.DescriptorProtos.MessageOptions>.ExtensionWriter
           extensionWriter = newExtensionWriter();
       if (((bitField0_ & 0x00000001) != 0)) {
@@ -30487,20 +30487,20 @@ public static com.google.protobuf.DescriptorProtos.MessageOptions parseFrom(
     }
     public static com.google.protobuf.DescriptorProtos.MessageOptions parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.MessageOptions parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.MessageOptions parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -30508,20 +30508,20 @@ public static com.google.protobuf.DescriptorProtos.MessageOptions parseDelimited
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.MessageOptions parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.MessageOptions parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -30541,7 +30541,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -30549,7 +30549,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.MessageOptions}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<
+        com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<
           com.google.protobuf.DescriptorProtos.MessageOptions, Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.MessageOptions)
         com.google.protobuf.DescriptorProtos.MessageOptionsOrBuilder {
@@ -30559,7 +30559,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_MessageOptions_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -30572,12 +30572,12 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
         maybeForceBuilderInitialization();
       }
       private void maybeForceBuilderInitialization() {
-        if (com.google.protobuf.GeneratedMessageV3
+        if (com.google.protobuf.GeneratedMessageV3Internal
                 .alwaysUseFieldBuilders) {
           getFeaturesFieldBuilder();
           getUninterpretedOptionFieldBuilder();
@@ -30712,33 +30712,33 @@ public Builder addRepeatedField(
           java.lang.Object value) {
         return super.addRepeatedField(field, value);
       }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.MessageOptions, Type> extension,
-          Type value) {
-        return super.setExtension(extension, value);
-      }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.MessageOptions, java.util.List<Type>> extension,
-          int index, Type value) {
-        return super.setExtension(extension, index, value);
-      }
-      @java.lang.Override
-      public <Type> Builder addExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.MessageOptions, java.util.List<Type>> extension,
-          Type value) {
-        return super.addExtension(extension, value);
-      }
-      @java.lang.Override
-      public <T> Builder clearExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.MessageOptions, T> extension) {
-        return super.clearExtension(extension);
-      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.MessageOptions, Type> extension,
+//          Type value) {
+//        return super.setExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.MessageOptions, java.util.List<Type>> extension,
+//          int index, Type value) {
+//        return super.setExtension(extension, index, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder addExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.MessageOptions, java.util.List<Type>> extension,
+//          Type value) {
+//        return super.addExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <T> Builder clearExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.MessageOptions, T> extension) {
+//        return super.clearExtension(extension);
+//      }
       @java.lang.Override
       public Builder mergeFrom(com.google.protobuf.Message other) {
         if (other instanceof com.google.protobuf.DescriptorProtos.MessageOptions) {
@@ -30788,7 +30788,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.MessageOptions oth
               uninterpretedOption_ = other.uninterpretedOption_;
               bitField0_ = (bitField0_ & ~0x00000040);
               uninterpretedOptionBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getUninterpretedOptionFieldBuilder() : null;
             } else {
               uninterpretedOptionBuilder_.addAllMessages(other.uninterpretedOption_);
@@ -31390,8 +31390,8 @@ public Builder clearMapEntry() {
       }
 
       private com.google.protobuf.DescriptorProtos.FeatureSet features_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> featuresBuilder_;
+      private SingleFieldBuilderV3Internal<
+                FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder> featuresBuilder_;
       /**
        * <pre>
        * Any features defined in the specific edition.
@@ -31559,12 +31559,12 @@ public com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder getFeaturesOrBui
        *
        * <code>optional .google.protobuf.FeatureSet features = 12;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>
           getFeaturesFieldBuilder() {
         if (featuresBuilder_ == null) {
-          featuresBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder>(
+          featuresBuilder_ = new SingleFieldBuilderV3Internal<
+                        FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>(
                   getFeatures(),
                   getParentForChildren(),
                   isClean());
@@ -31582,8 +31582,8 @@ private void ensureUninterpretedOptionIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder> uninterpretedOptionBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder> uninterpretedOptionBuilder_;
 
       /**
        * <pre>
@@ -31754,7 +31754,7 @@ public Builder addAllUninterpretedOption(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.UninterpretedOption> values) {
         if (uninterpretedOptionBuilder_ == null) {
           ensureUninterpretedOptionIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, uninterpretedOption_);
           onChanged();
         } else {
@@ -31870,12 +31870,12 @@ public com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder addUnint
            getUninterpretedOptionBuilderList() {
         return getUninterpretedOptionFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder>
           getUninterpretedOptionFieldBuilder() {
         if (uninterpretedOptionBuilder_ == null) {
-          uninterpretedOptionBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder>(
+          uninterpretedOptionBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder>(
                   uninterpretedOption_,
                   ((bitField0_ & 0x00000040) != 0),
                   getParentForChildren(),
@@ -31950,7 +31950,7 @@ public com.google.protobuf.DescriptorProtos.MessageOptions getDefaultInstanceFor
 
   public interface FieldOptionsOrBuilder extends
       // @@protoc_insertion_point(interface_extends:google.protobuf.FieldOptions)
-      com.google.protobuf.GeneratedMessageV3.
+      com.google.protobuf.GeneratedMessageV3Internal.
           ExtendableMessageOrBuilder<FieldOptions> {
 
     /**
@@ -32354,13 +32354,13 @@ com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder getUninterpret
    * Protobuf type {@code google.protobuf.FieldOptions}
    */
   public static final class FieldOptions extends
-      com.google.protobuf.GeneratedMessageV3.ExtendableMessage<
+      com.google.protobuf.GeneratedMessageV3Internal.ExtendableMessage<
         FieldOptions> implements
       // @@protoc_insertion_point(message_implements:google.protobuf.FieldOptions)
       FieldOptionsOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use FieldOptions.newBuilder() to construct.
-    private FieldOptions(com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<com.google.protobuf.DescriptorProtos.FieldOptions, ?> builder) {
+    private FieldOptions(com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<com.google.protobuf.DescriptorProtos.FieldOptions, ?> builder) {
       super(builder);
     }
     private FieldOptions() {
@@ -32385,7 +32385,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FieldOptions_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -32983,12 +32983,12 @@ public interface EditionDefaultOrBuilder extends
      * Protobuf type {@code google.protobuf.FieldOptions.EditionDefault}
      */
     public static final class EditionDefault extends
-        com.google.protobuf.GeneratedMessageV3 implements
+        com.google.protobuf.GeneratedMessageV3Internal implements
         // @@protoc_insertion_point(message_implements:google.protobuf.FieldOptions.EditionDefault)
         EditionDefaultOrBuilder {
     private static final long serialVersionUID = 0L;
       // Use EditionDefault.newBuilder() to construct.
-      private EditionDefault(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+      private EditionDefault(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
         super(builder);
       }
       private EditionDefault() {
@@ -33009,7 +33009,7 @@ protected java.lang.Object newInstance(
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FieldOptions_EditionDefault_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -33111,7 +33111,7 @@ public final boolean isInitialized() {
       public void writeTo(com.google.protobuf.CodedOutputStream output)
                           throws java.io.IOException {
         if (((bitField0_ & 0x00000002) != 0)) {
-          com.google.protobuf.GeneratedMessageV3.writeString(output, 2, value_);
+          com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 2, value_);
         }
         if (((bitField0_ & 0x00000001) != 0)) {
           output.writeEnum(3, edition_);
@@ -33126,7 +33126,7 @@ public int getSerializedSize() {
 
         size = 0;
         if (((bitField0_ & 0x00000002) != 0)) {
-          size += com.google.protobuf.GeneratedMessageV3.computeStringSize(2, value_);
+          size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(2, value_);
         }
         if (((bitField0_ & 0x00000001) != 0)) {
           size += com.google.protobuf.CodedOutputStream
@@ -33214,20 +33214,20 @@ public static com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefault p
       }
       public static com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefault parseFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefault parseFrom(
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
       public static com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefault parseDelimitedFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input);
       }
 
@@ -33235,20 +33235,20 @@ public static com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefault p
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
       }
       public static com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefault parseFrom(
           com.google.protobuf.CodedInputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefault parseFrom(
           com.google.protobuf.CodedInputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
@@ -33268,7 +33268,7 @@ public Builder toBuilder() {
 
       @java.lang.Override
       protected Builder newBuilderForType(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         Builder builder = new Builder(parent);
         return builder;
       }
@@ -33276,7 +33276,7 @@ protected Builder newBuilderForType(
        * Protobuf type {@code google.protobuf.FieldOptions.EditionDefault}
        */
       public static final class Builder extends
-          com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+          com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
           // @@protoc_insertion_point(builder_implements:google.protobuf.FieldOptions.EditionDefault)
           com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefaultOrBuilder {
         public static final com.google.protobuf.Descriptors.Descriptor
@@ -33285,7 +33285,7 @@ public static final class Builder extends
         }
 
         @java.lang.Override
-        protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
             internalGetFieldAccessorTable() {
           return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FieldOptions_EditionDefault_fieldAccessorTable
               .ensureFieldAccessorsInitialized(
@@ -33298,7 +33298,7 @@ private Builder() {
         }
 
         private Builder(
-            com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+            com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
           super(parent);
 
         }
@@ -33785,12 +33785,12 @@ public interface FeatureSupportOrBuilder extends
      * Protobuf type {@code google.protobuf.FieldOptions.FeatureSupport}
      */
     public static final class FeatureSupport extends
-        com.google.protobuf.GeneratedMessageV3 implements
+        com.google.protobuf.GeneratedMessageV3Internal implements
         // @@protoc_insertion_point(message_implements:google.protobuf.FieldOptions.FeatureSupport)
         FeatureSupportOrBuilder {
     private static final long serialVersionUID = 0L;
       // Use FeatureSupport.newBuilder() to construct.
-      private FeatureSupport(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+      private FeatureSupport(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
         super(builder);
       }
       private FeatureSupport() {
@@ -33813,7 +33813,7 @@ protected java.lang.Object newInstance(
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FieldOptions_FeatureSupport_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -33994,7 +33994,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output)
           output.writeEnum(2, editionDeprecated_);
         }
         if (((bitField0_ & 0x00000004) != 0)) {
-          com.google.protobuf.GeneratedMessageV3.writeString(output, 3, deprecationWarning_);
+          com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 3, deprecationWarning_);
         }
         if (((bitField0_ & 0x00000008) != 0)) {
           output.writeEnum(4, editionRemoved_);
@@ -34017,7 +34017,7 @@ public int getSerializedSize() {
             .computeEnumSize(2, editionDeprecated_);
         }
         if (((bitField0_ & 0x00000004) != 0)) {
-          size += com.google.protobuf.GeneratedMessageV3.computeStringSize(3, deprecationWarning_);
+          size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(3, deprecationWarning_);
         }
         if (((bitField0_ & 0x00000008) != 0)) {
           size += com.google.protobuf.CodedOutputStream
@@ -34121,20 +34121,20 @@ public static com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport p
       }
       public static com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport parseFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport parseFrom(
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
       public static com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport parseDelimitedFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input);
       }
 
@@ -34142,20 +34142,20 @@ public static com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport p
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
       }
       public static com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport parseFrom(
           com.google.protobuf.CodedInputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport parseFrom(
           com.google.protobuf.CodedInputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
@@ -34175,7 +34175,7 @@ public Builder toBuilder() {
 
       @java.lang.Override
       protected Builder newBuilderForType(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         Builder builder = new Builder(parent);
         return builder;
       }
@@ -34187,7 +34187,7 @@ protected Builder newBuilderForType(
        * Protobuf type {@code google.protobuf.FieldOptions.FeatureSupport}
        */
       public static final class Builder extends
-          com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+          com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
           // @@protoc_insertion_point(builder_implements:google.protobuf.FieldOptions.FeatureSupport)
           com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupportOrBuilder {
         public static final com.google.protobuf.Descriptors.Descriptor
@@ -34196,7 +34196,7 @@ public static final class Builder extends
         }
 
         @java.lang.Override
-        protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
             internalGetFieldAccessorTable() {
           return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FieldOptions_FeatureSupport_fieldAccessorTable
               .ensureFieldAccessorsInitialized(
@@ -34209,7 +34209,7 @@ private Builder() {
         }
 
         private Builder(
-            com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+            com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
           super(parent);
 
         }
@@ -35358,7 +35358,7 @@ public final boolean isInitialized() {
     @java.lang.Override
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
-      com.google.protobuf.GeneratedMessageV3
+      com.google.protobuf.GeneratedMessageV3Internal
         .ExtendableMessage<com.google.protobuf.DescriptorProtos.FieldOptions>.ExtensionWriter
           extensionWriter = newExtensionWriter();
       if (((bitField0_ & 0x00000001) != 0)) {
@@ -35662,20 +35662,20 @@ public static com.google.protobuf.DescriptorProtos.FieldOptions parseFrom(
     }
     public static com.google.protobuf.DescriptorProtos.FieldOptions parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.FieldOptions parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.FieldOptions parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -35683,20 +35683,20 @@ public static com.google.protobuf.DescriptorProtos.FieldOptions parseDelimitedFr
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.FieldOptions parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.FieldOptions parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -35716,7 +35716,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -35724,7 +35724,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.FieldOptions}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<
+        com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<
           com.google.protobuf.DescriptorProtos.FieldOptions, Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.FieldOptions)
         com.google.protobuf.DescriptorProtos.FieldOptionsOrBuilder {
@@ -35734,7 +35734,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FieldOptions_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -35747,12 +35747,12 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
         maybeForceBuilderInitialization();
       }
       private void maybeForceBuilderInitialization() {
-        if (com.google.protobuf.GeneratedMessageV3
+        if (com.google.protobuf.GeneratedMessageV3Internal
                 .alwaysUseFieldBuilders) {
           getEditionDefaultsFieldBuilder();
           getFeaturesFieldBuilder();
@@ -35943,33 +35943,33 @@ public Builder addRepeatedField(
           java.lang.Object value) {
         return super.addRepeatedField(field, value);
       }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.FieldOptions, Type> extension,
-          Type value) {
-        return super.setExtension(extension, value);
-      }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.FieldOptions, java.util.List<Type>> extension,
-          int index, Type value) {
-        return super.setExtension(extension, index, value);
-      }
-      @java.lang.Override
-      public <Type> Builder addExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.FieldOptions, java.util.List<Type>> extension,
-          Type value) {
-        return super.addExtension(extension, value);
-      }
-      @java.lang.Override
-      public <T> Builder clearExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.FieldOptions, T> extension) {
-        return super.clearExtension(extension);
-      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.FieldOptions, Type> extension,
+//          Type value) {
+//        return super.setExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.FieldOptions, java.util.List<Type>> extension,
+//          int index, Type value) {
+//        return super.setExtension(extension, index, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder addExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.FieldOptions, java.util.List<Type>> extension,
+//          Type value) {
+//        return super.addExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <T> Builder clearExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.FieldOptions, T> extension) {
+//        return super.clearExtension(extension);
+//      }
       @java.lang.Override
       public Builder mergeFrom(com.google.protobuf.Message other) {
         if (other instanceof com.google.protobuf.DescriptorProtos.FieldOptions) {
@@ -36038,7 +36038,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.FieldOptions other
               editionDefaults_ = other.editionDefaults_;
               bitField0_ = (bitField0_ & ~0x00000400);
               editionDefaultsBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getEditionDefaultsFieldBuilder() : null;
             } else {
               editionDefaultsBuilder_.addAllMessages(other.editionDefaults_);
@@ -36070,7 +36070,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.FieldOptions other
               uninterpretedOption_ = other.uninterpretedOption_;
               bitField0_ = (bitField0_ & ~0x00002000);
               uninterpretedOptionBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getUninterpretedOptionFieldBuilder() : null;
             } else {
               uninterpretedOptionBuilder_.addAllMessages(other.uninterpretedOption_);
@@ -37054,8 +37054,8 @@ private void ensureEditionDefaultsIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefault, com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefault.Builder, com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefaultOrBuilder> editionDefaultsBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                EditionDefault, EditionDefault.Builder, EditionDefaultOrBuilder> editionDefaultsBuilder_;
 
       /**
        * <code>repeated .google.protobuf.FieldOptions.EditionDefault edition_defaults = 20;</code>
@@ -37186,7 +37186,7 @@ public Builder addAllEditionDefaults(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefault> values) {
         if (editionDefaultsBuilder_ == null) {
           ensureEditionDefaultsIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, editionDefaults_);
           onChanged();
         } else {
@@ -37270,12 +37270,12 @@ public com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefault.Builder
            getEditionDefaultsBuilderList() {
         return getEditionDefaultsFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefault, com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefault.Builder, com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefaultOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                EditionDefault, EditionDefault.Builder, EditionDefaultOrBuilder>
           getEditionDefaultsFieldBuilder() {
         if (editionDefaultsBuilder_ == null) {
-          editionDefaultsBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefault, com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefault.Builder, com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefaultOrBuilder>(
+          editionDefaultsBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        EditionDefault, EditionDefault.Builder, EditionDefaultOrBuilder>(
                   editionDefaults_,
                   ((bitField0_ & 0x00000400) != 0),
                   getParentForChildren(),
@@ -37286,8 +37286,8 @@ public com.google.protobuf.DescriptorProtos.FieldOptions.EditionDefault.Builder
       }
 
       private com.google.protobuf.DescriptorProtos.FeatureSet features_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> featuresBuilder_;
+      private SingleFieldBuilderV3Internal<
+                FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder> featuresBuilder_;
       /**
        * <pre>
        * Any features defined in the specific edition.
@@ -37455,12 +37455,12 @@ public com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder getFeaturesOrBui
        *
        * <code>optional .google.protobuf.FeatureSet features = 21;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>
           getFeaturesFieldBuilder() {
         if (featuresBuilder_ == null) {
-          featuresBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder>(
+          featuresBuilder_ = new SingleFieldBuilderV3Internal<
+                        FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>(
                   getFeatures(),
                   getParentForChildren(),
                   isClean());
@@ -37470,8 +37470,8 @@ public com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder getFeaturesOrBui
       }
 
       private com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport featureSupport_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport, com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport.Builder, com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupportOrBuilder> featureSupportBuilder_;
+      private SingleFieldBuilderV3Internal<
+                FeatureSupport, FeatureSupport.Builder, FeatureSupportOrBuilder> featureSupportBuilder_;
       /**
        * <code>optional .google.protobuf.FieldOptions.FeatureSupport feature_support = 22;</code>
        * @return Whether the featureSupport field is set.
@@ -37576,12 +37576,12 @@ public com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupportOrBuilder
       /**
        * <code>optional .google.protobuf.FieldOptions.FeatureSupport feature_support = 22;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport, com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport.Builder, com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupportOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                FeatureSupport, FeatureSupport.Builder, FeatureSupportOrBuilder>
           getFeatureSupportFieldBuilder() {
         if (featureSupportBuilder_ == null) {
-          featureSupportBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport, com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport.Builder, com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupportOrBuilder>(
+          featureSupportBuilder_ = new SingleFieldBuilderV3Internal<
+                        FeatureSupport, FeatureSupport.Builder, FeatureSupportOrBuilder>(
                   getFeatureSupport(),
                   getParentForChildren(),
                   isClean());
@@ -37599,8 +37599,8 @@ private void ensureUninterpretedOptionIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder> uninterpretedOptionBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder> uninterpretedOptionBuilder_;
 
       /**
        * <pre>
@@ -37771,7 +37771,7 @@ public Builder addAllUninterpretedOption(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.UninterpretedOption> values) {
         if (uninterpretedOptionBuilder_ == null) {
           ensureUninterpretedOptionIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, uninterpretedOption_);
           onChanged();
         } else {
@@ -37887,12 +37887,12 @@ public com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder addUnint
            getUninterpretedOptionBuilderList() {
         return getUninterpretedOptionFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder>
           getUninterpretedOptionFieldBuilder() {
         if (uninterpretedOptionBuilder_ == null) {
-          uninterpretedOptionBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder>(
+          uninterpretedOptionBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder>(
                   uninterpretedOption_,
                   ((bitField0_ & 0x00002000) != 0),
                   getParentForChildren(),
@@ -37967,7 +37967,7 @@ public com.google.protobuf.DescriptorProtos.FieldOptions getDefaultInstanceForTy
 
   public interface OneofOptionsOrBuilder extends
       // @@protoc_insertion_point(interface_extends:google.protobuf.OneofOptions)
-      com.google.protobuf.GeneratedMessageV3.
+      com.google.protobuf.GeneratedMessageV3Internal.
           ExtendableMessageOrBuilder<OneofOptions> {
 
     /**
@@ -38054,13 +38054,13 @@ com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder getUninterpret
    * Protobuf type {@code google.protobuf.OneofOptions}
    */
   public static final class OneofOptions extends
-      com.google.protobuf.GeneratedMessageV3.ExtendableMessage<
+      com.google.protobuf.GeneratedMessageV3Internal.ExtendableMessage<
         OneofOptions> implements
       // @@protoc_insertion_point(message_implements:google.protobuf.OneofOptions)
       OneofOptionsOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use OneofOptions.newBuilder() to construct.
-    private OneofOptions(com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<com.google.protobuf.DescriptorProtos.OneofOptions, ?> builder) {
+    private OneofOptions(com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<com.google.protobuf.DescriptorProtos.OneofOptions, ?> builder) {
       super(builder);
     }
     private OneofOptions() {
@@ -38080,7 +38080,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_OneofOptions_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -38226,7 +38226,7 @@ public final boolean isInitialized() {
     @java.lang.Override
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
-      com.google.protobuf.GeneratedMessageV3
+      com.google.protobuf.GeneratedMessageV3Internal
         .ExtendableMessage<com.google.protobuf.DescriptorProtos.OneofOptions>.ExtensionWriter
           extensionWriter = newExtensionWriter();
       if (((bitField0_ & 0x00000001) != 0)) {
@@ -38337,20 +38337,20 @@ public static com.google.protobuf.DescriptorProtos.OneofOptions parseFrom(
     }
     public static com.google.protobuf.DescriptorProtos.OneofOptions parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.OneofOptions parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.OneofOptions parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -38358,20 +38358,20 @@ public static com.google.protobuf.DescriptorProtos.OneofOptions parseDelimitedFr
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.OneofOptions parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.OneofOptions parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -38391,7 +38391,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -38399,7 +38399,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.OneofOptions}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<
+        com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<
           com.google.protobuf.DescriptorProtos.OneofOptions, Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.OneofOptions)
         com.google.protobuf.DescriptorProtos.OneofOptionsOrBuilder {
@@ -38409,7 +38409,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_OneofOptions_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -38422,12 +38422,12 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
         maybeForceBuilderInitialization();
       }
       private void maybeForceBuilderInitialization() {
-        if (com.google.protobuf.GeneratedMessageV3
+        if (com.google.protobuf.GeneratedMessageV3Internal
                 .alwaysUseFieldBuilders) {
           getFeaturesFieldBuilder();
           getUninterpretedOptionFieldBuilder();
@@ -38537,33 +38537,33 @@ public Builder addRepeatedField(
           java.lang.Object value) {
         return super.addRepeatedField(field, value);
       }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.OneofOptions, Type> extension,
-          Type value) {
-        return super.setExtension(extension, value);
-      }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.OneofOptions, java.util.List<Type>> extension,
-          int index, Type value) {
-        return super.setExtension(extension, index, value);
-      }
-      @java.lang.Override
-      public <Type> Builder addExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.OneofOptions, java.util.List<Type>> extension,
-          Type value) {
-        return super.addExtension(extension, value);
-      }
-      @java.lang.Override
-      public <T> Builder clearExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.OneofOptions, T> extension) {
-        return super.clearExtension(extension);
-      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.OneofOptions, Type> extension,
+//          Type value) {
+//        return super.setExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.OneofOptions, java.util.List<Type>> extension,
+//          int index, Type value) {
+//        return super.setExtension(extension, index, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder addExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.OneofOptions, java.util.List<Type>> extension,
+//          Type value) {
+//        return super.addExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <T> Builder clearExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.OneofOptions, T> extension) {
+//        return super.clearExtension(extension);
+//      }
       @java.lang.Override
       public Builder mergeFrom(com.google.protobuf.Message other) {
         if (other instanceof com.google.protobuf.DescriptorProtos.OneofOptions) {
@@ -38598,7 +38598,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.OneofOptions other
               uninterpretedOption_ = other.uninterpretedOption_;
               bitField0_ = (bitField0_ & ~0x00000002);
               uninterpretedOptionBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getUninterpretedOptionFieldBuilder() : null;
             } else {
               uninterpretedOptionBuilder_.addAllMessages(other.uninterpretedOption_);
@@ -38683,8 +38683,8 @@ public Builder mergeFrom(
       private int bitField0_;
 
       private com.google.protobuf.DescriptorProtos.FeatureSet features_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> featuresBuilder_;
+      private SingleFieldBuilderV3Internal<
+                FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder> featuresBuilder_;
       /**
        * <pre>
        * Any features defined in the specific edition.
@@ -38852,12 +38852,12 @@ public com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder getFeaturesOrBui
        *
        * <code>optional .google.protobuf.FeatureSet features = 1;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>
           getFeaturesFieldBuilder() {
         if (featuresBuilder_ == null) {
-          featuresBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder>(
+          featuresBuilder_ = new SingleFieldBuilderV3Internal<
+                        FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>(
                   getFeatures(),
                   getParentForChildren(),
                   isClean());
@@ -38875,8 +38875,8 @@ private void ensureUninterpretedOptionIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder> uninterpretedOptionBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder> uninterpretedOptionBuilder_;
 
       /**
        * <pre>
@@ -39047,7 +39047,7 @@ public Builder addAllUninterpretedOption(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.UninterpretedOption> values) {
         if (uninterpretedOptionBuilder_ == null) {
           ensureUninterpretedOptionIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, uninterpretedOption_);
           onChanged();
         } else {
@@ -39163,12 +39163,12 @@ public com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder addUnint
            getUninterpretedOptionBuilderList() {
         return getUninterpretedOptionFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder>
           getUninterpretedOptionFieldBuilder() {
         if (uninterpretedOptionBuilder_ == null) {
-          uninterpretedOptionBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder>(
+          uninterpretedOptionBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder>(
                   uninterpretedOption_,
                   ((bitField0_ & 0x00000002) != 0),
                   getParentForChildren(),
@@ -39243,7 +39243,7 @@ public com.google.protobuf.DescriptorProtos.OneofOptions getDefaultInstanceForTy
 
   public interface EnumOptionsOrBuilder extends
       // @@protoc_insertion_point(interface_extends:google.protobuf.EnumOptions)
-      com.google.protobuf.GeneratedMessageV3.
+      com.google.protobuf.GeneratedMessageV3Internal.
           ExtendableMessageOrBuilder<EnumOptions> {
 
     /**
@@ -39409,13 +39409,13 @@ com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder getUninterpret
    * Protobuf type {@code google.protobuf.EnumOptions}
    */
   public static final class EnumOptions extends
-      com.google.protobuf.GeneratedMessageV3.ExtendableMessage<
+      com.google.protobuf.GeneratedMessageV3Internal.ExtendableMessage<
         EnumOptions> implements
       // @@protoc_insertion_point(message_implements:google.protobuf.EnumOptions)
       EnumOptionsOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use EnumOptions.newBuilder() to construct.
-    private EnumOptions(com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<com.google.protobuf.DescriptorProtos.EnumOptions, ?> builder) {
+    private EnumOptions(com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<com.google.protobuf.DescriptorProtos.EnumOptions, ?> builder) {
       super(builder);
     }
     private EnumOptions() {
@@ -39435,7 +39435,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_EnumOptions_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -39684,7 +39684,7 @@ public final boolean isInitialized() {
     @java.lang.Override
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
-      com.google.protobuf.GeneratedMessageV3
+      com.google.protobuf.GeneratedMessageV3Internal
         .ExtendableMessage<com.google.protobuf.DescriptorProtos.EnumOptions>.ExtensionWriter
           extensionWriter = newExtensionWriter();
       if (((bitField0_ & 0x00000001) != 0)) {
@@ -39846,20 +39846,20 @@ public static com.google.protobuf.DescriptorProtos.EnumOptions parseFrom(
     }
     public static com.google.protobuf.DescriptorProtos.EnumOptions parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.EnumOptions parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.EnumOptions parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -39867,20 +39867,20 @@ public static com.google.protobuf.DescriptorProtos.EnumOptions parseDelimitedFro
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.EnumOptions parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.EnumOptions parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -39900,7 +39900,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -39908,7 +39908,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.EnumOptions}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<
+        com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<
           com.google.protobuf.DescriptorProtos.EnumOptions, Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.EnumOptions)
         com.google.protobuf.DescriptorProtos.EnumOptionsOrBuilder {
@@ -39918,7 +39918,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_EnumOptions_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -39931,12 +39931,12 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
         maybeForceBuilderInitialization();
       }
       private void maybeForceBuilderInitialization() {
-        if (com.google.protobuf.GeneratedMessageV3
+        if (com.google.protobuf.GeneratedMessageV3Internal
                 .alwaysUseFieldBuilders) {
           getFeaturesFieldBuilder();
           getUninterpretedOptionFieldBuilder();
@@ -40061,33 +40061,33 @@ public Builder addRepeatedField(
           java.lang.Object value) {
         return super.addRepeatedField(field, value);
       }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.EnumOptions, Type> extension,
-          Type value) {
-        return super.setExtension(extension, value);
-      }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.EnumOptions, java.util.List<Type>> extension,
-          int index, Type value) {
-        return super.setExtension(extension, index, value);
-      }
-      @java.lang.Override
-      public <Type> Builder addExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.EnumOptions, java.util.List<Type>> extension,
-          Type value) {
-        return super.addExtension(extension, value);
-      }
-      @java.lang.Override
-      public <T> Builder clearExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.EnumOptions, T> extension) {
-        return super.clearExtension(extension);
-      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.EnumOptions, Type> extension,
+//          Type value) {
+//        return super.setExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.EnumOptions, java.util.List<Type>> extension,
+//          int index, Type value) {
+//        return super.setExtension(extension, index, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder addExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.EnumOptions, java.util.List<Type>> extension,
+//          Type value) {
+//        return super.addExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <T> Builder clearExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.EnumOptions, T> extension) {
+//        return super.clearExtension(extension);
+//      }
       @java.lang.Override
       public Builder mergeFrom(com.google.protobuf.Message other) {
         if (other instanceof com.google.protobuf.DescriptorProtos.EnumOptions) {
@@ -40131,7 +40131,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.EnumOptions other)
               uninterpretedOption_ = other.uninterpretedOption_;
               bitField0_ = (bitField0_ & ~0x00000010);
               uninterpretedOptionBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getUninterpretedOptionFieldBuilder() : null;
             } else {
               uninterpretedOptionBuilder_.addAllMessages(other.uninterpretedOption_);
@@ -40443,8 +40443,8 @@ public Builder clearDeprecated() {
       }
 
       private com.google.protobuf.DescriptorProtos.FeatureSet features_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> featuresBuilder_;
+      private SingleFieldBuilderV3Internal<
+                FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder> featuresBuilder_;
       /**
        * <pre>
        * Any features defined in the specific edition.
@@ -40612,12 +40612,12 @@ public com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder getFeaturesOrBui
        *
        * <code>optional .google.protobuf.FeatureSet features = 7;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>
           getFeaturesFieldBuilder() {
         if (featuresBuilder_ == null) {
-          featuresBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder>(
+          featuresBuilder_ = new SingleFieldBuilderV3Internal<
+                        FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>(
                   getFeatures(),
                   getParentForChildren(),
                   isClean());
@@ -40635,8 +40635,8 @@ private void ensureUninterpretedOptionIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder> uninterpretedOptionBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder> uninterpretedOptionBuilder_;
 
       /**
        * <pre>
@@ -40807,7 +40807,7 @@ public Builder addAllUninterpretedOption(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.UninterpretedOption> values) {
         if (uninterpretedOptionBuilder_ == null) {
           ensureUninterpretedOptionIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, uninterpretedOption_);
           onChanged();
         } else {
@@ -40923,12 +40923,12 @@ public com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder addUnint
            getUninterpretedOptionBuilderList() {
         return getUninterpretedOptionFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder>
           getUninterpretedOptionFieldBuilder() {
         if (uninterpretedOptionBuilder_ == null) {
-          uninterpretedOptionBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder>(
+          uninterpretedOptionBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder>(
                   uninterpretedOption_,
                   ((bitField0_ & 0x00000010) != 0),
                   getParentForChildren(),
@@ -41003,7 +41003,7 @@ public com.google.protobuf.DescriptorProtos.EnumOptions getDefaultInstanceForTyp
 
   public interface EnumValueOptionsOrBuilder extends
       // @@protoc_insertion_point(interface_extends:google.protobuf.EnumValueOptions)
-      com.google.protobuf.GeneratedMessageV3.
+      com.google.protobuf.GeneratedMessageV3Internal.
           ExtendableMessageOrBuilder<EnumValueOptions> {
 
     /**
@@ -41165,13 +41165,13 @@ com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder getUninterpret
    * Protobuf type {@code google.protobuf.EnumValueOptions}
    */
   public static final class EnumValueOptions extends
-      com.google.protobuf.GeneratedMessageV3.ExtendableMessage<
+      com.google.protobuf.GeneratedMessageV3Internal.ExtendableMessage<
         EnumValueOptions> implements
       // @@protoc_insertion_point(message_implements:google.protobuf.EnumValueOptions)
       EnumValueOptionsOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use EnumValueOptions.newBuilder() to construct.
-    private EnumValueOptions(com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<com.google.protobuf.DescriptorProtos.EnumValueOptions, ?> builder) {
+    private EnumValueOptions(com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<com.google.protobuf.DescriptorProtos.EnumValueOptions, ?> builder) {
       super(builder);
     }
     private EnumValueOptions() {
@@ -41191,7 +41191,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_EnumValueOptions_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -41439,7 +41439,7 @@ public final boolean isInitialized() {
     @java.lang.Override
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
-      com.google.protobuf.GeneratedMessageV3
+      com.google.protobuf.GeneratedMessageV3Internal
         .ExtendableMessage<com.google.protobuf.DescriptorProtos.EnumValueOptions>.ExtensionWriter
           extensionWriter = newExtensionWriter();
       if (((bitField0_ & 0x00000001) != 0)) {
@@ -41600,20 +41600,20 @@ public static com.google.protobuf.DescriptorProtos.EnumValueOptions parseFrom(
     }
     public static com.google.protobuf.DescriptorProtos.EnumValueOptions parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.EnumValueOptions parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.EnumValueOptions parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -41621,20 +41621,20 @@ public static com.google.protobuf.DescriptorProtos.EnumValueOptions parseDelimit
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.EnumValueOptions parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.EnumValueOptions parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -41654,7 +41654,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -41662,7 +41662,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.EnumValueOptions}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<
+        com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<
           com.google.protobuf.DescriptorProtos.EnumValueOptions, Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.EnumValueOptions)
         com.google.protobuf.DescriptorProtos.EnumValueOptionsOrBuilder {
@@ -41672,7 +41672,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_EnumValueOptions_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -41685,12 +41685,12 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
         maybeForceBuilderInitialization();
       }
       private void maybeForceBuilderInitialization() {
-        if (com.google.protobuf.GeneratedMessageV3
+        if (com.google.protobuf.GeneratedMessageV3Internal
                 .alwaysUseFieldBuilders) {
           getFeaturesFieldBuilder();
           getFeatureSupportFieldBuilder();
@@ -41822,33 +41822,33 @@ public Builder addRepeatedField(
           java.lang.Object value) {
         return super.addRepeatedField(field, value);
       }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.EnumValueOptions, Type> extension,
-          Type value) {
-        return super.setExtension(extension, value);
-      }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.EnumValueOptions, java.util.List<Type>> extension,
-          int index, Type value) {
-        return super.setExtension(extension, index, value);
-      }
-      @java.lang.Override
-      public <Type> Builder addExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.EnumValueOptions, java.util.List<Type>> extension,
-          Type value) {
-        return super.addExtension(extension, value);
-      }
-      @java.lang.Override
-      public <T> Builder clearExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.EnumValueOptions, T> extension) {
-        return super.clearExtension(extension);
-      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.EnumValueOptions, Type> extension,
+//          Type value) {
+//        return super.setExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.EnumValueOptions, java.util.List<Type>> extension,
+//          int index, Type value) {
+//        return super.setExtension(extension, index, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder addExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.EnumValueOptions, java.util.List<Type>> extension,
+//          Type value) {
+//        return super.addExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <T> Builder clearExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.EnumValueOptions, T> extension) {
+//        return super.clearExtension(extension);
+//      }
       @java.lang.Override
       public Builder mergeFrom(com.google.protobuf.Message other) {
         if (other instanceof com.google.protobuf.DescriptorProtos.EnumValueOptions) {
@@ -41892,7 +41892,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.EnumValueOptions o
               uninterpretedOption_ = other.uninterpretedOption_;
               bitField0_ = (bitField0_ & ~0x00000010);
               uninterpretedOptionBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getUninterpretedOptionFieldBuilder() : null;
             } else {
               uninterpretedOptionBuilder_.addAllMessages(other.uninterpretedOption_);
@@ -42062,8 +42062,8 @@ public Builder clearDeprecated() {
       }
 
       private com.google.protobuf.DescriptorProtos.FeatureSet features_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> featuresBuilder_;
+      private SingleFieldBuilderV3Internal<
+                FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder> featuresBuilder_;
       /**
        * <pre>
        * Any features defined in the specific edition.
@@ -42231,12 +42231,12 @@ public com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder getFeaturesOrBui
        *
        * <code>optional .google.protobuf.FeatureSet features = 2;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>
           getFeaturesFieldBuilder() {
         if (featuresBuilder_ == null) {
-          featuresBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder>(
+          featuresBuilder_ = new SingleFieldBuilderV3Internal<
+                        FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>(
                   getFeatures(),
                   getParentForChildren(),
                   isClean());
@@ -42310,8 +42310,8 @@ public Builder clearDebugRedact() {
       }
 
       private com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport featureSupport_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport, com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport.Builder, com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupportOrBuilder> featureSupportBuilder_;
+      private SingleFieldBuilderV3Internal<
+                FieldOptions.FeatureSupport, FieldOptions.FeatureSupport.Builder, FieldOptions.FeatureSupportOrBuilder> featureSupportBuilder_;
       /**
        * <pre>
        * Information about the support window of a feature value.
@@ -42452,12 +42452,12 @@ public com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupportOrBuilder
        *
        * <code>optional .google.protobuf.FieldOptions.FeatureSupport feature_support = 4;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport, com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport.Builder, com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupportOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                FieldOptions.FeatureSupport, FieldOptions.FeatureSupport.Builder, FieldOptions.FeatureSupportOrBuilder>
           getFeatureSupportFieldBuilder() {
         if (featureSupportBuilder_ == null) {
-          featureSupportBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport, com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupport.Builder, com.google.protobuf.DescriptorProtos.FieldOptions.FeatureSupportOrBuilder>(
+          featureSupportBuilder_ = new SingleFieldBuilderV3Internal<
+                        FieldOptions.FeatureSupport, FieldOptions.FeatureSupport.Builder, FieldOptions.FeatureSupportOrBuilder>(
                   getFeatureSupport(),
                   getParentForChildren(),
                   isClean());
@@ -42475,8 +42475,8 @@ private void ensureUninterpretedOptionIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder> uninterpretedOptionBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder> uninterpretedOptionBuilder_;
 
       /**
        * <pre>
@@ -42647,7 +42647,7 @@ public Builder addAllUninterpretedOption(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.UninterpretedOption> values) {
         if (uninterpretedOptionBuilder_ == null) {
           ensureUninterpretedOptionIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, uninterpretedOption_);
           onChanged();
         } else {
@@ -42763,12 +42763,12 @@ public com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder addUnint
            getUninterpretedOptionBuilderList() {
         return getUninterpretedOptionFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder>
           getUninterpretedOptionFieldBuilder() {
         if (uninterpretedOptionBuilder_ == null) {
-          uninterpretedOptionBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder>(
+          uninterpretedOptionBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder>(
                   uninterpretedOption_,
                   ((bitField0_ & 0x00000010) != 0),
                   getParentForChildren(),
@@ -42843,7 +42843,7 @@ public com.google.protobuf.DescriptorProtos.EnumValueOptions getDefaultInstanceF
 
   public interface ServiceOptionsOrBuilder extends
       // @@protoc_insertion_point(interface_extends:google.protobuf.ServiceOptions)
-      com.google.protobuf.GeneratedMessageV3.
+      com.google.protobuf.GeneratedMessageV3Internal.
           ExtendableMessageOrBuilder<ServiceOptions> {
 
     /**
@@ -42955,13 +42955,13 @@ com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder getUninterpret
    * Protobuf type {@code google.protobuf.ServiceOptions}
    */
   public static final class ServiceOptions extends
-      com.google.protobuf.GeneratedMessageV3.ExtendableMessage<
+      com.google.protobuf.GeneratedMessageV3Internal.ExtendableMessage<
         ServiceOptions> implements
       // @@protoc_insertion_point(message_implements:google.protobuf.ServiceOptions)
       ServiceOptionsOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use ServiceOptions.newBuilder() to construct.
-    private ServiceOptions(com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<com.google.protobuf.DescriptorProtos.ServiceOptions, ?> builder) {
+    private ServiceOptions(com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<com.google.protobuf.DescriptorProtos.ServiceOptions, ?> builder) {
       super(builder);
     }
     private ServiceOptions() {
@@ -42981,7 +42981,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_ServiceOptions_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -43160,7 +43160,7 @@ public final boolean isInitialized() {
     @java.lang.Override
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
-      com.google.protobuf.GeneratedMessageV3
+      com.google.protobuf.GeneratedMessageV3Internal
         .ExtendableMessage<com.google.protobuf.DescriptorProtos.ServiceOptions>.ExtensionWriter
           extensionWriter = newExtensionWriter();
       if (((bitField0_ & 0x00000002) != 0)) {
@@ -43288,20 +43288,20 @@ public static com.google.protobuf.DescriptorProtos.ServiceOptions parseFrom(
     }
     public static com.google.protobuf.DescriptorProtos.ServiceOptions parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.ServiceOptions parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.ServiceOptions parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -43309,20 +43309,20 @@ public static com.google.protobuf.DescriptorProtos.ServiceOptions parseDelimited
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.ServiceOptions parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.ServiceOptions parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -43342,7 +43342,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -43350,7 +43350,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.ServiceOptions}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<
+        com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<
           com.google.protobuf.DescriptorProtos.ServiceOptions, Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.ServiceOptions)
         com.google.protobuf.DescriptorProtos.ServiceOptionsOrBuilder {
@@ -43360,7 +43360,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_ServiceOptions_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -43373,12 +43373,12 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
         maybeForceBuilderInitialization();
       }
       private void maybeForceBuilderInitialization() {
-        if (com.google.protobuf.GeneratedMessageV3
+        if (com.google.protobuf.GeneratedMessageV3Internal
                 .alwaysUseFieldBuilders) {
           getFeaturesFieldBuilder();
           getUninterpretedOptionFieldBuilder();
@@ -43493,33 +43493,33 @@ public Builder addRepeatedField(
           java.lang.Object value) {
         return super.addRepeatedField(field, value);
       }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.ServiceOptions, Type> extension,
-          Type value) {
-        return super.setExtension(extension, value);
-      }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.ServiceOptions, java.util.List<Type>> extension,
-          int index, Type value) {
-        return super.setExtension(extension, index, value);
-      }
-      @java.lang.Override
-      public <Type> Builder addExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.ServiceOptions, java.util.List<Type>> extension,
-          Type value) {
-        return super.addExtension(extension, value);
-      }
-      @java.lang.Override
-      public <T> Builder clearExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.ServiceOptions, T> extension) {
-        return super.clearExtension(extension);
-      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.ServiceOptions, Type> extension,
+//          Type value) {
+//        return super.setExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.ServiceOptions, java.util.List<Type>> extension,
+//          int index, Type value) {
+//        return super.setExtension(extension, index, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder addExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.ServiceOptions, java.util.List<Type>> extension,
+//          Type value) {
+//        return super.addExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <T> Builder clearExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.ServiceOptions, T> extension) {
+//        return super.clearExtension(extension);
+//      }
       @java.lang.Override
       public Builder mergeFrom(com.google.protobuf.Message other) {
         if (other instanceof com.google.protobuf.DescriptorProtos.ServiceOptions) {
@@ -43557,7 +43557,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.ServiceOptions oth
               uninterpretedOption_ = other.uninterpretedOption_;
               bitField0_ = (bitField0_ & ~0x00000004);
               uninterpretedOptionBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getUninterpretedOptionFieldBuilder() : null;
             } else {
               uninterpretedOptionBuilder_.addAllMessages(other.uninterpretedOption_);
@@ -43647,8 +43647,8 @@ public Builder mergeFrom(
       private int bitField0_;
 
       private com.google.protobuf.DescriptorProtos.FeatureSet features_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> featuresBuilder_;
+      private SingleFieldBuilderV3Internal<
+                FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder> featuresBuilder_;
       /**
        * <pre>
        * Any features defined in the specific edition.
@@ -43816,12 +43816,12 @@ public com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder getFeaturesOrBui
        *
        * <code>optional .google.protobuf.FeatureSet features = 34;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>
           getFeaturesFieldBuilder() {
         if (featuresBuilder_ == null) {
-          featuresBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder>(
+          featuresBuilder_ = new SingleFieldBuilderV3Internal<
+                        FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>(
                   getFeatures(),
                   getParentForChildren(),
                   isClean());
@@ -43907,8 +43907,8 @@ private void ensureUninterpretedOptionIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder> uninterpretedOptionBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder> uninterpretedOptionBuilder_;
 
       /**
        * <pre>
@@ -44079,7 +44079,7 @@ public Builder addAllUninterpretedOption(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.UninterpretedOption> values) {
         if (uninterpretedOptionBuilder_ == null) {
           ensureUninterpretedOptionIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, uninterpretedOption_);
           onChanged();
         } else {
@@ -44195,12 +44195,12 @@ public com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder addUnint
            getUninterpretedOptionBuilderList() {
         return getUninterpretedOptionFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder>
           getUninterpretedOptionFieldBuilder() {
         if (uninterpretedOptionBuilder_ == null) {
-          uninterpretedOptionBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder>(
+          uninterpretedOptionBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder>(
                   uninterpretedOption_,
                   ((bitField0_ & 0x00000004) != 0),
                   getParentForChildren(),
@@ -44275,7 +44275,7 @@ public com.google.protobuf.DescriptorProtos.ServiceOptions getDefaultInstanceFor
 
   public interface MethodOptionsOrBuilder extends
       // @@protoc_insertion_point(interface_extends:google.protobuf.MethodOptions)
-      com.google.protobuf.GeneratedMessageV3.
+      com.google.protobuf.GeneratedMessageV3Internal.
           ExtendableMessageOrBuilder<MethodOptions> {
 
     /**
@@ -44398,13 +44398,13 @@ com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder getUninterpret
    * Protobuf type {@code google.protobuf.MethodOptions}
    */
   public static final class MethodOptions extends
-      com.google.protobuf.GeneratedMessageV3.ExtendableMessage<
+      com.google.protobuf.GeneratedMessageV3Internal.ExtendableMessage<
         MethodOptions> implements
       // @@protoc_insertion_point(message_implements:google.protobuf.MethodOptions)
       MethodOptionsOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use MethodOptions.newBuilder() to construct.
-    private MethodOptions(com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<com.google.protobuf.DescriptorProtos.MethodOptions, ?> builder) {
+    private MethodOptions(com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<com.google.protobuf.DescriptorProtos.MethodOptions, ?> builder) {
       super(builder);
     }
     private MethodOptions() {
@@ -44425,7 +44425,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_MethodOptions_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -44749,7 +44749,7 @@ public final boolean isInitialized() {
     @java.lang.Override
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
-      com.google.protobuf.GeneratedMessageV3
+      com.google.protobuf.GeneratedMessageV3Internal
         .ExtendableMessage<com.google.protobuf.DescriptorProtos.MethodOptions>.ExtensionWriter
           extensionWriter = newExtensionWriter();
       if (((bitField0_ & 0x00000001) != 0)) {
@@ -44892,20 +44892,20 @@ public static com.google.protobuf.DescriptorProtos.MethodOptions parseFrom(
     }
     public static com.google.protobuf.DescriptorProtos.MethodOptions parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.MethodOptions parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.MethodOptions parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -44913,20 +44913,20 @@ public static com.google.protobuf.DescriptorProtos.MethodOptions parseDelimitedF
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.MethodOptions parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.MethodOptions parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -44946,7 +44946,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -44954,7 +44954,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.MethodOptions}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<
+        com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<
           com.google.protobuf.DescriptorProtos.MethodOptions, Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.MethodOptions)
         com.google.protobuf.DescriptorProtos.MethodOptionsOrBuilder {
@@ -44964,7 +44964,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_MethodOptions_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -44977,12 +44977,12 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
         maybeForceBuilderInitialization();
       }
       private void maybeForceBuilderInitialization() {
-        if (com.google.protobuf.GeneratedMessageV3
+        if (com.google.protobuf.GeneratedMessageV3Internal
                 .alwaysUseFieldBuilders) {
           getFeaturesFieldBuilder();
           getUninterpretedOptionFieldBuilder();
@@ -45102,33 +45102,33 @@ public Builder addRepeatedField(
           java.lang.Object value) {
         return super.addRepeatedField(field, value);
       }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.MethodOptions, Type> extension,
-          Type value) {
-        return super.setExtension(extension, value);
-      }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.MethodOptions, java.util.List<Type>> extension,
-          int index, Type value) {
-        return super.setExtension(extension, index, value);
-      }
-      @java.lang.Override
-      public <Type> Builder addExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.MethodOptions, java.util.List<Type>> extension,
-          Type value) {
-        return super.addExtension(extension, value);
-      }
-      @java.lang.Override
-      public <T> Builder clearExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.MethodOptions, T> extension) {
-        return super.clearExtension(extension);
-      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.MethodOptions, Type> extension,
+//          Type value) {
+//        return super.setExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.MethodOptions, java.util.List<Type>> extension,
+//          int index, Type value) {
+//        return super.setExtension(extension, index, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder addExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.MethodOptions, java.util.List<Type>> extension,
+//          Type value) {
+//        return super.addExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <T> Builder clearExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.MethodOptions, T> extension) {
+//        return super.clearExtension(extension);
+//      }
       @java.lang.Override
       public Builder mergeFrom(com.google.protobuf.Message other) {
         if (other instanceof com.google.protobuf.DescriptorProtos.MethodOptions) {
@@ -45169,7 +45169,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.MethodOptions othe
               uninterpretedOption_ = other.uninterpretedOption_;
               bitField0_ = (bitField0_ & ~0x00000008);
               uninterpretedOptionBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getUninterpretedOptionFieldBuilder() : null;
             } else {
               uninterpretedOptionBuilder_.addAllMessages(other.uninterpretedOption_);
@@ -45381,8 +45381,8 @@ public Builder clearIdempotencyLevel() {
       }
 
       private com.google.protobuf.DescriptorProtos.FeatureSet features_;
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> featuresBuilder_;
+      private SingleFieldBuilderV3Internal<
+                FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder> featuresBuilder_;
       /**
        * <pre>
        * Any features defined in the specific edition.
@@ -45550,12 +45550,12 @@ public com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder getFeaturesOrBui
        *
        * <code>optional .google.protobuf.FeatureSet features = 35;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> 
+      private SingleFieldBuilderV3Internal<
+                FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>
           getFeaturesFieldBuilder() {
         if (featuresBuilder_ == null) {
-          featuresBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder>(
+          featuresBuilder_ = new SingleFieldBuilderV3Internal<
+                        FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>(
                   getFeatures(),
                   getParentForChildren(),
                   isClean());
@@ -45573,8 +45573,8 @@ private void ensureUninterpretedOptionIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder> uninterpretedOptionBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder> uninterpretedOptionBuilder_;
 
       /**
        * <pre>
@@ -45745,7 +45745,7 @@ public Builder addAllUninterpretedOption(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.UninterpretedOption> values) {
         if (uninterpretedOptionBuilder_ == null) {
           ensureUninterpretedOptionIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, uninterpretedOption_);
           onChanged();
         } else {
@@ -45861,12 +45861,12 @@ public com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder addUnint
            getUninterpretedOptionBuilderList() {
         return getUninterpretedOptionFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder>
           getUninterpretedOptionFieldBuilder() {
         if (uninterpretedOptionBuilder_ == null) {
-          uninterpretedOptionBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.UninterpretedOption, com.google.protobuf.DescriptorProtos.UninterpretedOption.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder>(
+          uninterpretedOptionBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        UninterpretedOption, UninterpretedOption.Builder, UninterpretedOptionOrBuilder>(
                   uninterpretedOption_,
                   ((bitField0_ & 0x00000008) != 0),
                   getParentForChildren(),
@@ -46073,12 +46073,12 @@ com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePartOrBuilder getNa
    * Protobuf type {@code google.protobuf.UninterpretedOption}
    */
   public static final class UninterpretedOption extends
-      com.google.protobuf.GeneratedMessageV3 implements
+      com.google.protobuf.GeneratedMessageV3Internal implements
       // @@protoc_insertion_point(message_implements:google.protobuf.UninterpretedOption)
       UninterpretedOptionOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use UninterpretedOption.newBuilder() to construct.
-    private UninterpretedOption(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    private UninterpretedOption(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
       super(builder);
     }
     private UninterpretedOption() {
@@ -46101,7 +46101,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_UninterpretedOption_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -46152,12 +46152,12 @@ public interface NamePartOrBuilder extends
      * Protobuf type {@code google.protobuf.UninterpretedOption.NamePart}
      */
     public static final class NamePart extends
-        com.google.protobuf.GeneratedMessageV3 implements
+        com.google.protobuf.GeneratedMessageV3Internal implements
         // @@protoc_insertion_point(message_implements:google.protobuf.UninterpretedOption.NamePart)
         NamePartOrBuilder {
     private static final long serialVersionUID = 0L;
       // Use NamePart.newBuilder() to construct.
-      private NamePart(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+      private NamePart(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
         super(builder);
       }
       private NamePart() {
@@ -46177,7 +46177,7 @@ protected java.lang.Object newInstance(
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_UninterpretedOption_NamePart_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -46276,7 +46276,7 @@ public final boolean isInitialized() {
       public void writeTo(com.google.protobuf.CodedOutputStream output)
                           throws java.io.IOException {
         if (((bitField0_ & 0x00000001) != 0)) {
-          com.google.protobuf.GeneratedMessageV3.writeString(output, 1, namePart_);
+          com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, namePart_);
         }
         if (((bitField0_ & 0x00000002) != 0)) {
           output.writeBool(2, isExtension_);
@@ -46291,7 +46291,7 @@ public int getSerializedSize() {
 
         size = 0;
         if (((bitField0_ & 0x00000001) != 0)) {
-          size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, namePart_);
+          size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(1, namePart_);
         }
         if (((bitField0_ & 0x00000002) != 0)) {
           size += com.google.protobuf.CodedOutputStream
@@ -46381,20 +46381,20 @@ public static com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePart
       }
       public static com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePart parseFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePart parseFrom(
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
       public static com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePart parseDelimitedFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input);
       }
 
@@ -46402,20 +46402,20 @@ public static com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePart
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
       }
       public static com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePart parseFrom(
           com.google.protobuf.CodedInputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePart parseFrom(
           com.google.protobuf.CodedInputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
@@ -46435,7 +46435,7 @@ public Builder toBuilder() {
 
       @java.lang.Override
       protected Builder newBuilderForType(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         Builder builder = new Builder(parent);
         return builder;
       }
@@ -46451,7 +46451,7 @@ protected Builder newBuilderForType(
        * Protobuf type {@code google.protobuf.UninterpretedOption.NamePart}
        */
       public static final class Builder extends
-          com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+          com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
           // @@protoc_insertion_point(builder_implements:google.protobuf.UninterpretedOption.NamePart)
           com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePartOrBuilder {
         public static final com.google.protobuf.Descriptors.Descriptor
@@ -46460,7 +46460,7 @@ public static final class Builder extends
         }
 
         @java.lang.Override
-        protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
             internalGetFieldAccessorTable() {
           return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_UninterpretedOption_NamePart_fieldAccessorTable
               .ensureFieldAccessorsInitialized(
@@ -46473,7 +46473,7 @@ private Builder() {
         }
 
         private Builder(
-            com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+            com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
           super(parent);
 
         }
@@ -47077,7 +47077,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output)
         output.writeMessage(2, name_.get(i));
       }
       if (((bitField0_ & 0x00000001) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 3, identifierValue_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 3, identifierValue_);
       }
       if (((bitField0_ & 0x00000002) != 0)) {
         output.writeUInt64(4, positiveIntValue_);
@@ -47092,7 +47092,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output)
         output.writeBytes(7, stringValue_);
       }
       if (((bitField0_ & 0x00000020) != 0)) {
-        com.google.protobuf.GeneratedMessageV3.writeString(output, 8, aggregateValue_);
+        com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 8, aggregateValue_);
       }
       getUnknownFields().writeTo(output);
     }
@@ -47108,7 +47108,7 @@ public int getSerializedSize() {
           .computeMessageSize(2, name_.get(i));
       }
       if (((bitField0_ & 0x00000001) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(3, identifierValue_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(3, identifierValue_);
       }
       if (((bitField0_ & 0x00000002) != 0)) {
         size += com.google.protobuf.CodedOutputStream
@@ -47127,7 +47127,7 @@ public int getSerializedSize() {
           .computeBytesSize(7, stringValue_);
       }
       if (((bitField0_ & 0x00000020) != 0)) {
-        size += com.google.protobuf.GeneratedMessageV3.computeStringSize(8, aggregateValue_);
+        size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(8, aggregateValue_);
       }
       size += getUnknownFields().getSerializedSize();
       memoizedSize = size;
@@ -47258,20 +47258,20 @@ public static com.google.protobuf.DescriptorProtos.UninterpretedOption parseFrom
     }
     public static com.google.protobuf.DescriptorProtos.UninterpretedOption parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.UninterpretedOption parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.UninterpretedOption parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -47279,20 +47279,20 @@ public static com.google.protobuf.DescriptorProtos.UninterpretedOption parseDeli
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.UninterpretedOption parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.UninterpretedOption parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -47312,7 +47312,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -47329,7 +47329,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.UninterpretedOption}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+        com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.UninterpretedOption)
         com.google.protobuf.DescriptorProtos.UninterpretedOptionOrBuilder {
       public static final com.google.protobuf.Descriptors.Descriptor
@@ -47338,7 +47338,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_UninterpretedOption_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -47351,7 +47351,7 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
 
       }
@@ -47509,7 +47509,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.UninterpretedOptio
               name_ = other.name_;
               bitField0_ = (bitField0_ & ~0x00000001);
               nameBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getNameFieldBuilder() : null;
             } else {
               nameBuilder_.addAllMessages(other.name_);
@@ -47638,8 +47638,8 @@ private void ensureNameIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePart, com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePart.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePartOrBuilder> nameBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                NamePart, NamePart.Builder, NamePartOrBuilder> nameBuilder_;
 
       /**
        * <code>repeated .google.protobuf.UninterpretedOption.NamePart name = 2;</code>
@@ -47770,7 +47770,7 @@ public Builder addAllName(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePart> values) {
         if (nameBuilder_ == null) {
           ensureNameIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, name_);
           onChanged();
         } else {
@@ -47854,12 +47854,12 @@ public com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePart.Builder
            getNameBuilderList() {
         return getNameFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePart, com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePart.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePartOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                NamePart, NamePart.Builder, NamePartOrBuilder>
           getNameFieldBuilder() {
         if (nameBuilder_ == null) {
-          nameBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePart, com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePart.Builder, com.google.protobuf.DescriptorProtos.UninterpretedOption.NamePartOrBuilder>(
+          nameBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        NamePart, NamePart.Builder, NamePartOrBuilder>(
                   name_,
                   ((bitField0_ & 0x00000001) != 0),
                   getParentForChildren(),
@@ -48284,7 +48284,7 @@ public com.google.protobuf.DescriptorProtos.UninterpretedOption getDefaultInstan
 
   public interface FeatureSetOrBuilder extends
       // @@protoc_insertion_point(interface_extends:google.protobuf.FeatureSet)
-      com.google.protobuf.GeneratedMessageV3.
+      com.google.protobuf.GeneratedMessageV3Internal.
           ExtendableMessageOrBuilder<FeatureSet> {
 
     /**
@@ -48366,13 +48366,13 @@ public interface FeatureSetOrBuilder extends
    * Protobuf type {@code google.protobuf.FeatureSet}
    */
   public static final class FeatureSet extends
-      com.google.protobuf.GeneratedMessageV3.ExtendableMessage<
+      com.google.protobuf.GeneratedMessageV3Internal.ExtendableMessage<
         FeatureSet> implements
       // @@protoc_insertion_point(message_implements:google.protobuf.FeatureSet)
       FeatureSetOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use FeatureSet.newBuilder() to construct.
-    private FeatureSet(com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<com.google.protobuf.DescriptorProtos.FeatureSet, ?> builder) {
+    private FeatureSet(com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<com.google.protobuf.DescriptorProtos.FeatureSet, ?> builder) {
       super(builder);
     }
     private FeatureSet() {
@@ -48397,7 +48397,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FeatureSet_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -49170,7 +49170,7 @@ public final boolean isInitialized() {
     @java.lang.Override
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
-      com.google.protobuf.GeneratedMessageV3
+      com.google.protobuf.GeneratedMessageV3Internal
         .ExtendableMessage<com.google.protobuf.DescriptorProtos.FeatureSet>.ExtensionWriter
           extensionWriter = newExtensionWriter();
       if (((bitField0_ & 0x00000001) != 0)) {
@@ -49342,20 +49342,20 @@ public static com.google.protobuf.DescriptorProtos.FeatureSet parseFrom(
     }
     public static com.google.protobuf.DescriptorProtos.FeatureSet parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.FeatureSet parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.FeatureSet parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -49363,20 +49363,20 @@ public static com.google.protobuf.DescriptorProtos.FeatureSet parseDelimitedFrom
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.FeatureSet parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.FeatureSet parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -49396,7 +49396,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -49413,7 +49413,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.FeatureSet}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<
+        com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<
           com.google.protobuf.DescriptorProtos.FeatureSet, Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.FeatureSet)
         com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder {
@@ -49423,7 +49423,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FeatureSet_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -49436,7 +49436,7 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
 
       }
@@ -49543,33 +49543,33 @@ public Builder addRepeatedField(
           java.lang.Object value) {
         return super.addRepeatedField(field, value);
       }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.FeatureSet, Type> extension,
-          Type value) {
-        return super.setExtension(extension, value);
-      }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.FeatureSet, java.util.List<Type>> extension,
-          int index, Type value) {
-        return super.setExtension(extension, index, value);
-      }
-      @java.lang.Override
-      public <Type> Builder addExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.FeatureSet, java.util.List<Type>> extension,
-          Type value) {
-        return super.addExtension(extension, value);
-      }
-      @java.lang.Override
-      public <T> Builder clearExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.FeatureSet, T> extension) {
-        return super.clearExtension(extension);
-      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.FeatureSet, Type> extension,
+//          Type value) {
+//        return super.setExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.FeatureSet, java.util.List<Type>> extension,
+//          int index, Type value) {
+//        return super.setExtension(extension, index, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder addExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.FeatureSet, java.util.List<Type>> extension,
+//          Type value) {
+//        return super.addExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <T> Builder clearExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.FeatureSet, T> extension) {
+//        return super.clearExtension(extension);
+//      }
       @java.lang.Override
       public Builder mergeFrom(com.google.protobuf.Message other) {
         if (other instanceof com.google.protobuf.DescriptorProtos.FeatureSet) {
@@ -50115,12 +50115,12 @@ com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSetEditionDefault
    * Protobuf type {@code google.protobuf.FeatureSetDefaults}
    */
   public static final class FeatureSetDefaults extends
-      com.google.protobuf.GeneratedMessageV3 implements
+      com.google.protobuf.GeneratedMessageV3Internal implements
       // @@protoc_insertion_point(message_implements:google.protobuf.FeatureSetDefaults)
       FeatureSetDefaultsOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use FeatureSetDefaults.newBuilder() to construct.
-    private FeatureSetDefaults(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    private FeatureSetDefaults(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
       super(builder);
     }
     private FeatureSetDefaults() {
@@ -50142,7 +50142,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FeatureSetDefaults_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -50229,12 +50229,12 @@ public interface FeatureSetEditionDefaultOrBuilder extends
      * Protobuf type {@code google.protobuf.FeatureSetDefaults.FeatureSetEditionDefault}
      */
     public static final class FeatureSetEditionDefault extends
-        com.google.protobuf.GeneratedMessageV3 implements
+        com.google.protobuf.GeneratedMessageV3Internal implements
         // @@protoc_insertion_point(message_implements:google.protobuf.FeatureSetDefaults.FeatureSetEditionDefault)
         FeatureSetEditionDefaultOrBuilder {
     private static final long serialVersionUID = 0L;
       // Use FeatureSetEditionDefault.newBuilder() to construct.
-      private FeatureSetEditionDefault(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+      private FeatureSetEditionDefault(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
         super(builder);
       }
       private FeatureSetEditionDefault() {
@@ -50254,7 +50254,7 @@ protected java.lang.Object newInstance(
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FeatureSetDefaults_FeatureSetEditionDefault_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -50503,20 +50503,20 @@ public static com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSet
       }
       public static com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSetEditionDefault parseFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSetEditionDefault parseFrom(
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
       public static com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSetEditionDefault parseDelimitedFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input);
       }
 
@@ -50524,20 +50524,20 @@ public static com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSet
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
       }
       public static com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSetEditionDefault parseFrom(
           com.google.protobuf.CodedInputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSetEditionDefault parseFrom(
           com.google.protobuf.CodedInputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
@@ -50557,7 +50557,7 @@ public Builder toBuilder() {
 
       @java.lang.Override
       protected Builder newBuilderForType(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         Builder builder = new Builder(parent);
         return builder;
       }
@@ -50572,7 +50572,7 @@ protected Builder newBuilderForType(
        * Protobuf type {@code google.protobuf.FeatureSetDefaults.FeatureSetEditionDefault}
        */
       public static final class Builder extends
-          com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+          com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
           // @@protoc_insertion_point(builder_implements:google.protobuf.FeatureSetDefaults.FeatureSetEditionDefault)
           com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSetEditionDefaultOrBuilder {
         public static final com.google.protobuf.Descriptors.Descriptor
@@ -50581,7 +50581,7 @@ public static final class Builder extends
         }
 
         @java.lang.Override
-        protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
             internalGetFieldAccessorTable() {
           return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FeatureSetDefaults_FeatureSetEditionDefault_fieldAccessorTable
               .ensureFieldAccessorsInitialized(
@@ -50594,12 +50594,12 @@ private Builder() {
         }
 
         private Builder(
-            com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+            com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
           super(parent);
           maybeForceBuilderInitialization();
         }
         private void maybeForceBuilderInitialization() {
-          if (com.google.protobuf.GeneratedMessageV3
+          if (com.google.protobuf.GeneratedMessageV3Internal
                   .alwaysUseFieldBuilders) {
             getOverridableFeaturesFieldBuilder();
             getFixedFeaturesFieldBuilder();
@@ -50848,8 +50848,8 @@ public Builder clearEdition() {
         }
 
         private com.google.protobuf.DescriptorProtos.FeatureSet overridableFeatures_;
-        private com.google.protobuf.SingleFieldBuilderV3<
-            com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> overridableFeaturesBuilder_;
+        private SingleFieldBuilderV3Internal<
+                    FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder> overridableFeaturesBuilder_;
         /**
          * <pre>
          * Defaults of features that can be overridden in this edition.
@@ -50990,12 +50990,12 @@ public com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder getOverridableFe
          *
          * <code>optional .google.protobuf.FeatureSet overridable_features = 4;</code>
          */
-        private com.google.protobuf.SingleFieldBuilderV3<
-            com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> 
+        private SingleFieldBuilderV3Internal<
+                    FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>
             getOverridableFeaturesFieldBuilder() {
           if (overridableFeaturesBuilder_ == null) {
-            overridableFeaturesBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-                com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder>(
+            overridableFeaturesBuilder_ = new SingleFieldBuilderV3Internal<
+                            FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>(
                     getOverridableFeatures(),
                     getParentForChildren(),
                     isClean());
@@ -51005,8 +51005,8 @@ public com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder getOverridableFe
         }
 
         private com.google.protobuf.DescriptorProtos.FeatureSet fixedFeatures_;
-        private com.google.protobuf.SingleFieldBuilderV3<
-            com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> fixedFeaturesBuilder_;
+        private SingleFieldBuilderV3Internal<
+                    FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder> fixedFeaturesBuilder_;
         /**
          * <pre>
          * Defaults of features that can't be overridden in this edition.
@@ -51147,12 +51147,12 @@ public com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder getFixedFeatures
          *
          * <code>optional .google.protobuf.FeatureSet fixed_features = 5;</code>
          */
-        private com.google.protobuf.SingleFieldBuilderV3<
-            com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder> 
+        private SingleFieldBuilderV3Internal<
+                    FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>
             getFixedFeaturesFieldBuilder() {
           if (fixedFeaturesBuilder_ == null) {
-            fixedFeaturesBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-                com.google.protobuf.DescriptorProtos.FeatureSet, com.google.protobuf.DescriptorProtos.FeatureSet.Builder, com.google.protobuf.DescriptorProtos.FeatureSetOrBuilder>(
+            fixedFeaturesBuilder_ = new SingleFieldBuilderV3Internal<
+                            FeatureSet, FeatureSet.Builder, FeatureSetOrBuilder>(
                     getFixedFeatures(),
                     getParentForChildren(),
                     isClean());
@@ -51459,20 +51459,20 @@ public static com.google.protobuf.DescriptorProtos.FeatureSetDefaults parseFrom(
     }
     public static com.google.protobuf.DescriptorProtos.FeatureSetDefaults parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.FeatureSetDefaults parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.FeatureSetDefaults parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -51480,20 +51480,20 @@ public static com.google.protobuf.DescriptorProtos.FeatureSetDefaults parseDelim
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.FeatureSetDefaults parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.FeatureSetDefaults parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -51513,7 +51513,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -51528,7 +51528,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.FeatureSetDefaults}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+        com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.FeatureSetDefaults)
         com.google.protobuf.DescriptorProtos.FeatureSetDefaultsOrBuilder {
       public static final com.google.protobuf.Descriptors.Descriptor
@@ -51537,7 +51537,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_FeatureSetDefaults_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -51550,7 +51550,7 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
 
       }
@@ -51688,7 +51688,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.FeatureSetDefaults
               defaults_ = other.defaults_;
               bitField0_ = (bitField0_ & ~0x00000001);
               defaultsBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getDefaultsFieldBuilder() : null;
             } else {
               defaultsBuilder_.addAllMessages(other.defaults_);
@@ -51795,8 +51795,8 @@ private void ensureDefaultsIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSetEditionDefault, com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSetEditionDefault.Builder, com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSetEditionDefaultOrBuilder> defaultsBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                FeatureSetEditionDefault, FeatureSetEditionDefault.Builder, FeatureSetEditionDefaultOrBuilder> defaultsBuilder_;
 
       /**
        * <code>repeated .google.protobuf.FeatureSetDefaults.FeatureSetEditionDefault defaults = 1;</code>
@@ -51927,7 +51927,7 @@ public Builder addAllDefaults(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSetEditionDefault> values) {
         if (defaultsBuilder_ == null) {
           ensureDefaultsIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, defaults_);
           onChanged();
         } else {
@@ -52011,12 +52011,12 @@ public com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSetEdition
            getDefaultsBuilderList() {
         return getDefaultsFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSetEditionDefault, com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSetEditionDefault.Builder, com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSetEditionDefaultOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                FeatureSetEditionDefault, FeatureSetEditionDefault.Builder, FeatureSetEditionDefaultOrBuilder>
           getDefaultsFieldBuilder() {
         if (defaultsBuilder_ == null) {
-          defaultsBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSetEditionDefault, com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSetEditionDefault.Builder, com.google.protobuf.DescriptorProtos.FeatureSetDefaults.FeatureSetEditionDefaultOrBuilder>(
+          defaultsBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        FeatureSetEditionDefault, FeatureSetEditionDefault.Builder, FeatureSetEditionDefaultOrBuilder>(
                   defaults_,
                   ((bitField0_ & 0x00000001) != 0),
                   getParentForChildren(),
@@ -52215,7 +52215,7 @@ public com.google.protobuf.DescriptorProtos.FeatureSetDefaults getDefaultInstanc
 
   public interface SourceCodeInfoOrBuilder extends
       // @@protoc_insertion_point(interface_extends:google.protobuf.SourceCodeInfo)
-      com.google.protobuf.GeneratedMessageV3.
+      com.google.protobuf.GeneratedMessageV3Internal.
           ExtendableMessageOrBuilder<SourceCodeInfo> {
 
     /**
@@ -52481,13 +52481,13 @@ com.google.protobuf.DescriptorProtos.SourceCodeInfo.LocationOrBuilder getLocatio
    * Protobuf type {@code google.protobuf.SourceCodeInfo}
    */
   public static final class SourceCodeInfo extends
-      com.google.protobuf.GeneratedMessageV3.ExtendableMessage<
+      com.google.protobuf.GeneratedMessageV3Internal.ExtendableMessage<
         SourceCodeInfo> implements
       // @@protoc_insertion_point(message_implements:google.protobuf.SourceCodeInfo)
       SourceCodeInfoOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use SourceCodeInfo.newBuilder() to construct.
-    private SourceCodeInfo(com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<com.google.protobuf.DescriptorProtos.SourceCodeInfo, ?> builder) {
+    private SourceCodeInfo(com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<com.google.protobuf.DescriptorProtos.SourceCodeInfo, ?> builder) {
       super(builder);
     }
     private SourceCodeInfo() {
@@ -52507,7 +52507,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_SourceCodeInfo_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -52867,12 +52867,12 @@ public interface LocationOrBuilder extends
      * Protobuf type {@code google.protobuf.SourceCodeInfo.Location}
      */
     public static final class Location extends
-        com.google.protobuf.GeneratedMessageV3 implements
+        com.google.protobuf.GeneratedMessageV3Internal implements
         // @@protoc_insertion_point(message_implements:google.protobuf.SourceCodeInfo.Location)
         LocationOrBuilder {
     private static final long serialVersionUID = 0L;
       // Use Location.newBuilder() to construct.
-      private Location(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+      private Location(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
         super(builder);
       }
       private Location() {
@@ -52897,7 +52897,7 @@ protected java.lang.Object newInstance(
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_SourceCodeInfo_Location_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -53382,13 +53382,13 @@ public void writeTo(com.google.protobuf.CodedOutputStream output)
           output.writeInt32NoTag(span_.getInt(i));
         }
         if (((bitField0_ & 0x00000001) != 0)) {
-          com.google.protobuf.GeneratedMessageV3.writeString(output, 3, leadingComments_);
+          com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 3, leadingComments_);
         }
         if (((bitField0_ & 0x00000002) != 0)) {
-          com.google.protobuf.GeneratedMessageV3.writeString(output, 4, trailingComments_);
+          com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 4, trailingComments_);
         }
         for (int i = 0; i < leadingDetachedComments_.size(); i++) {
-          com.google.protobuf.GeneratedMessageV3.writeString(output, 6, leadingDetachedComments_.getRaw(i));
+          com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 6, leadingDetachedComments_.getRaw(i));
         }
         getUnknownFields().writeTo(output);
       }
@@ -53428,10 +53428,10 @@ public int getSerializedSize() {
           spanMemoizedSerializedSize = dataSize;
         }
         if (((bitField0_ & 0x00000001) != 0)) {
-          size += com.google.protobuf.GeneratedMessageV3.computeStringSize(3, leadingComments_);
+          size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(3, leadingComments_);
         }
         if (((bitField0_ & 0x00000002) != 0)) {
-          size += com.google.protobuf.GeneratedMessageV3.computeStringSize(4, trailingComments_);
+          size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(4, trailingComments_);
         }
         {
           int dataSize = 0;
@@ -53542,20 +53542,20 @@ public static com.google.protobuf.DescriptorProtos.SourceCodeInfo.Location parse
       }
       public static com.google.protobuf.DescriptorProtos.SourceCodeInfo.Location parseFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.SourceCodeInfo.Location parseFrom(
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
       public static com.google.protobuf.DescriptorProtos.SourceCodeInfo.Location parseDelimitedFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input);
       }
 
@@ -53563,20 +53563,20 @@ public static com.google.protobuf.DescriptorProtos.SourceCodeInfo.Location parse
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
       }
       public static com.google.protobuf.DescriptorProtos.SourceCodeInfo.Location parseFrom(
           com.google.protobuf.CodedInputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.SourceCodeInfo.Location parseFrom(
           com.google.protobuf.CodedInputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
@@ -53596,7 +53596,7 @@ public Builder toBuilder() {
 
       @java.lang.Override
       protected Builder newBuilderForType(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         Builder builder = new Builder(parent);
         return builder;
       }
@@ -53604,7 +53604,7 @@ protected Builder newBuilderForType(
        * Protobuf type {@code google.protobuf.SourceCodeInfo.Location}
        */
       public static final class Builder extends
-          com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+          com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
           // @@protoc_insertion_point(builder_implements:google.protobuf.SourceCodeInfo.Location)
           com.google.protobuf.DescriptorProtos.SourceCodeInfo.LocationOrBuilder {
         public static final com.google.protobuf.Descriptors.Descriptor
@@ -53613,7 +53613,7 @@ public static final class Builder extends
         }
 
         @java.lang.Override
-        protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
             internalGetFieldAccessorTable() {
           return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_SourceCodeInfo_Location_fieldAccessorTable
               .ensureFieldAccessorsInitialized(
@@ -53626,7 +53626,7 @@ private Builder() {
         }
 
         private Builder(
-            com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+            com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
           super(parent);
 
         }
@@ -54097,7 +54097,7 @@ public Builder addPath(int value) {
         public Builder addAllPath(
             java.lang.Iterable<? extends java.lang.Integer> values) {
           ensurePathIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, path_);
           bitField0_ |= 0x00000001;
           onChanged();
@@ -54255,7 +54255,7 @@ public Builder addSpan(int value) {
         public Builder addAllSpan(
             java.lang.Iterable<? extends java.lang.Integer> values) {
           ensureSpanIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, span_);
           bitField0_ |= 0x00000002;
           onChanged();
@@ -54818,7 +54818,7 @@ public Builder addLeadingDetachedComments(
         public Builder addAllLeadingDetachedComments(
             java.lang.Iterable<java.lang.String> values) {
           ensureLeadingDetachedCommentsIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, leadingDetachedComments_);
           bitField0_ |= 0x00000010;
           onChanged();
@@ -55202,7 +55202,7 @@ public final boolean isInitialized() {
     @java.lang.Override
     public void writeTo(com.google.protobuf.CodedOutputStream output)
                         throws java.io.IOException {
-      com.google.protobuf.GeneratedMessageV3
+      com.google.protobuf.GeneratedMessageV3Internal
         .ExtendableMessage<com.google.protobuf.DescriptorProtos.SourceCodeInfo>.ExtensionWriter
           extensionWriter = newExtensionWriter();
       for (int i = 0; i < location_.size(); i++) {
@@ -55297,20 +55297,20 @@ public static com.google.protobuf.DescriptorProtos.SourceCodeInfo parseFrom(
     }
     public static com.google.protobuf.DescriptorProtos.SourceCodeInfo parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.SourceCodeInfo parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.SourceCodeInfo parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -55318,20 +55318,20 @@ public static com.google.protobuf.DescriptorProtos.SourceCodeInfo parseDelimited
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.SourceCodeInfo parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.SourceCodeInfo parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -55351,7 +55351,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -55364,7 +55364,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.SourceCodeInfo}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.ExtendableBuilder<
+        com.google.protobuf.GeneratedMessageV3Internal.ExtendableBuilder<
           com.google.protobuf.DescriptorProtos.SourceCodeInfo, Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.SourceCodeInfo)
         com.google.protobuf.DescriptorProtos.SourceCodeInfoOrBuilder {
@@ -55374,7 +55374,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_SourceCodeInfo_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -55387,7 +55387,7 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
 
       }
@@ -55482,33 +55482,33 @@ public Builder addRepeatedField(
           java.lang.Object value) {
         return super.addRepeatedField(field, value);
       }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.SourceCodeInfo, Type> extension,
-          Type value) {
-        return super.setExtension(extension, value);
-      }
-      @java.lang.Override
-      public <Type> Builder setExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.SourceCodeInfo, java.util.List<Type>> extension,
-          int index, Type value) {
-        return super.setExtension(extension, index, value);
-      }
-      @java.lang.Override
-      public <Type> Builder addExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.SourceCodeInfo, java.util.List<Type>> extension,
-          Type value) {
-        return super.addExtension(extension, value);
-      }
-      @java.lang.Override
-      public <T> Builder clearExtension(
-          com.google.protobuf.GeneratedMessage.GeneratedExtension<
-              com.google.protobuf.DescriptorProtos.SourceCodeInfo, T> extension) {
-        return super.clearExtension(extension);
-      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.SourceCodeInfo, Type> extension,
+//          Type value) {
+//        return super.setExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder setExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.SourceCodeInfo, java.util.List<Type>> extension,
+//          int index, Type value) {
+//        return super.setExtension(extension, index, value);
+//      }
+//      @java.lang.Override
+//      public <Type> Builder addExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.SourceCodeInfo, java.util.List<Type>> extension,
+//          Type value) {
+//        return super.addExtension(extension, value);
+//      }
+//      @java.lang.Override
+//      public <T> Builder clearExtension(
+//          com.google.protobuf.GeneratedMessage.GeneratedExtension<
+//              com.google.protobuf.DescriptorProtos.SourceCodeInfo, T> extension) {
+//        return super.clearExtension(extension);
+//      }
       @java.lang.Override
       public Builder mergeFrom(com.google.protobuf.Message other) {
         if (other instanceof com.google.protobuf.DescriptorProtos.SourceCodeInfo) {
@@ -55540,7 +55540,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.SourceCodeInfo oth
               location_ = other.location_;
               bitField0_ = (bitField0_ & ~0x00000001);
               locationBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getLocationFieldBuilder() : null;
             } else {
               locationBuilder_.addAllMessages(other.location_);
@@ -55616,8 +55616,8 @@ private void ensureLocationIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.SourceCodeInfo.Location, com.google.protobuf.DescriptorProtos.SourceCodeInfo.Location.Builder, com.google.protobuf.DescriptorProtos.SourceCodeInfo.LocationOrBuilder> locationBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                Location, Location.Builder, LocationOrBuilder> locationBuilder_;
 
       /**
        * <pre>
@@ -56208,7 +56208,7 @@ public Builder addAllLocation(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.SourceCodeInfo.Location> values) {
         if (locationBuilder_ == null) {
           ensureLocationIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, location_);
           onChanged();
         } else {
@@ -56660,12 +56660,12 @@ public com.google.protobuf.DescriptorProtos.SourceCodeInfo.Location.Builder addL
            getLocationBuilderList() {
         return getLocationFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.SourceCodeInfo.Location, com.google.protobuf.DescriptorProtos.SourceCodeInfo.Location.Builder, com.google.protobuf.DescriptorProtos.SourceCodeInfo.LocationOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                Location, Location.Builder, LocationOrBuilder>
           getLocationFieldBuilder() {
         if (locationBuilder_ == null) {
-          locationBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.SourceCodeInfo.Location, com.google.protobuf.DescriptorProtos.SourceCodeInfo.Location.Builder, com.google.protobuf.DescriptorProtos.SourceCodeInfo.LocationOrBuilder>(
+          locationBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        Location, Location.Builder, LocationOrBuilder>(
                   location_,
                   ((bitField0_ & 0x00000001) != 0),
                   getParentForChildren(),
@@ -56801,12 +56801,12 @@ com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.AnnotationOrBuilder getAn
    * Protobuf type {@code google.protobuf.GeneratedCodeInfo}
    */
   public static final class GeneratedCodeInfo extends
-      com.google.protobuf.GeneratedMessageV3 implements
+      com.google.protobuf.GeneratedMessageV3Internal implements
       // @@protoc_insertion_point(message_implements:google.protobuf.GeneratedCodeInfo)
       GeneratedCodeInfoOrBuilder {
   private static final long serialVersionUID = 0L;
     // Use GeneratedCodeInfo.newBuilder() to construct.
-    private GeneratedCodeInfo(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    private GeneratedCodeInfo(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
       super(builder);
     }
     private GeneratedCodeInfo() {
@@ -56826,7 +56826,7 @@ protected java.lang.Object newInstance(
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_GeneratedCodeInfo_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -56957,12 +56957,12 @@ public interface AnnotationOrBuilder extends
      * Protobuf type {@code google.protobuf.GeneratedCodeInfo.Annotation}
      */
     public static final class Annotation extends
-        com.google.protobuf.GeneratedMessageV3 implements
+        com.google.protobuf.GeneratedMessageV3Internal implements
         // @@protoc_insertion_point(message_implements:google.protobuf.GeneratedCodeInfo.Annotation)
         AnnotationOrBuilder {
     private static final long serialVersionUID = 0L;
       // Use Annotation.newBuilder() to construct.
-      private Annotation(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+      private Annotation(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
         super(builder);
       }
       private Annotation() {
@@ -56984,7 +56984,7 @@ protected java.lang.Object newInstance(
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_GeneratedCodeInfo_Annotation_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -57333,7 +57333,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output)
           output.writeInt32NoTag(path_.getInt(i));
         }
         if (((bitField0_ & 0x00000001) != 0)) {
-          com.google.protobuf.GeneratedMessageV3.writeString(output, 2, sourceFile_);
+          com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 2, sourceFile_);
         }
         if (((bitField0_ & 0x00000002) != 0)) {
           output.writeInt32(3, begin_);
@@ -57368,7 +57368,7 @@ public int getSerializedSize() {
           pathMemoizedSerializedSize = dataSize;
         }
         if (((bitField0_ & 0x00000001) != 0)) {
-          size += com.google.protobuf.GeneratedMessageV3.computeStringSize(2, sourceFile_);
+          size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(2, sourceFile_);
         }
         if (((bitField0_ & 0x00000002) != 0)) {
           size += com.google.protobuf.CodedOutputStream
@@ -57488,20 +57488,20 @@ public static com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.Annotation
       }
       public static com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.Annotation parseFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.Annotation parseFrom(
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
       public static com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.Annotation parseDelimitedFrom(java.io.InputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input);
       }
 
@@ -57509,20 +57509,20 @@ public static com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.Annotation
           java.io.InputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
       }
       public static com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.Annotation parseFrom(
           com.google.protobuf.CodedInputStream input)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input);
       }
       public static com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.Annotation parseFrom(
           com.google.protobuf.CodedInputStream input,
           com.google.protobuf.ExtensionRegistryLite extensionRegistry)
           throws java.io.IOException {
-        return com.google.protobuf.GeneratedMessageV3
+        return com.google.protobuf.GeneratedMessageV3Internal
             .parseWithIOException(PARSER, input, extensionRegistry);
       }
 
@@ -57542,7 +57542,7 @@ public Builder toBuilder() {
 
       @java.lang.Override
       protected Builder newBuilderForType(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         Builder builder = new Builder(parent);
         return builder;
       }
@@ -57550,7 +57550,7 @@ protected Builder newBuilderForType(
        * Protobuf type {@code google.protobuf.GeneratedCodeInfo.Annotation}
        */
       public static final class Builder extends
-          com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+          com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
           // @@protoc_insertion_point(builder_implements:google.protobuf.GeneratedCodeInfo.Annotation)
           com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.AnnotationOrBuilder {
         public static final com.google.protobuf.Descriptors.Descriptor
@@ -57559,7 +57559,7 @@ public static final class Builder extends
         }
 
         @java.lang.Override
-        protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
             internalGetFieldAccessorTable() {
           return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_GeneratedCodeInfo_Annotation_fieldAccessorTable
               .ensureFieldAccessorsInitialized(
@@ -57572,7 +57572,7 @@ private Builder() {
         }
 
         private Builder(
-            com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+            com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
           super(parent);
 
         }
@@ -57894,7 +57894,7 @@ public Builder addPath(int value) {
         public Builder addAllPath(
             java.lang.Iterable<? extends java.lang.Integer> values) {
           ensurePathIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, path_);
           bitField0_ |= 0x00000001;
           onChanged();
@@ -58416,20 +58416,20 @@ public static com.google.protobuf.DescriptorProtos.GeneratedCodeInfo parseFrom(
     }
     public static com.google.protobuf.DescriptorProtos.GeneratedCodeInfo parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.GeneratedCodeInfo parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.DescriptorProtos.GeneratedCodeInfo parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input);
     }
 
@@ -58437,20 +58437,20 @@ public static com.google.protobuf.DescriptorProtos.GeneratedCodeInfo parseDelimi
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.DescriptorProtos.GeneratedCodeInfo parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.DescriptorProtos.GeneratedCodeInfo parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
+      return com.google.protobuf.GeneratedMessageV3Internal
           .parseWithIOException(PARSER, input, extensionRegistry);
     }
 
@@ -58470,7 +58470,7 @@ public Builder toBuilder() {
 
     @java.lang.Override
     protected Builder newBuilderForType(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       Builder builder = new Builder(parent);
       return builder;
     }
@@ -58484,7 +58484,7 @@ protected Builder newBuilderForType(
      * Protobuf type {@code google.protobuf.GeneratedCodeInfo}
      */
     public static final class Builder extends
-        com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+        com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
         // @@protoc_insertion_point(builder_implements:google.protobuf.GeneratedCodeInfo)
         com.google.protobuf.DescriptorProtos.GeneratedCodeInfoOrBuilder {
       public static final com.google.protobuf.Descriptors.Descriptor
@@ -58493,7 +58493,7 @@ public static final class Builder extends
       }
 
       @java.lang.Override
-      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
           internalGetFieldAccessorTable() {
         return com.google.protobuf.DescriptorProtos.internal_static_google_protobuf_GeneratedCodeInfo_fieldAccessorTable
             .ensureFieldAccessorsInitialized(
@@ -58506,7 +58506,7 @@ private Builder() {
       }
 
       private Builder(
-          com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+          com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
         super(parent);
 
       }
@@ -58632,7 +58632,7 @@ public Builder mergeFrom(com.google.protobuf.DescriptorProtos.GeneratedCodeInfo
               annotation_ = other.annotation_;
               bitField0_ = (bitField0_ & ~0x00000001);
               annotationBuilder_ = 
-                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                    getAnnotationFieldBuilder() : null;
             } else {
               annotationBuilder_.addAllMessages(other.annotation_);
@@ -58704,8 +58704,8 @@ private void ensureAnnotationIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.Annotation, com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.Annotation.Builder, com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.AnnotationOrBuilder> annotationBuilder_;
+      private RepeatedFieldBuilderV3Internal<
+                Annotation, Annotation.Builder, AnnotationOrBuilder> annotationBuilder_;
 
       /**
        * <pre>
@@ -58886,7 +58886,7 @@ public Builder addAllAnnotation(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.Annotation> values) {
         if (annotationBuilder_ == null) {
           ensureAnnotationIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.GeneratedMessageV3Internal.Builder.addAll(
               values, annotation_);
           onChanged();
         } else {
@@ -59010,12 +59010,12 @@ public com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.Annotation.Builder
            getAnnotationBuilderList() {
         return getAnnotationFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
-          com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.Annotation, com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.Annotation.Builder, com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.AnnotationOrBuilder> 
+      private RepeatedFieldBuilderV3Internal<
+                Annotation, Annotation.Builder, AnnotationOrBuilder>
           getAnnotationFieldBuilder() {
         if (annotationBuilder_ == null) {
-          annotationBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-              com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.Annotation, com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.Annotation.Builder, com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.AnnotationOrBuilder>(
+          annotationBuilder_ = new RepeatedFieldBuilderV3Internal<
+                        Annotation, Annotation.Builder, AnnotationOrBuilder>(
                   annotation_,
                   ((bitField0_ & 0x00000001) != 0),
                   getParentForChildren(),
@@ -59091,167 +59091,167 @@ public com.google.protobuf.DescriptorProtos.GeneratedCodeInfo getDefaultInstance
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_FileDescriptorSet_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_FileDescriptorSet_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_FileDescriptorProto_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_FileDescriptorProto_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_DescriptorProto_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_DescriptorProto_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_DescriptorProto_ExtensionRange_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_DescriptorProto_ExtensionRange_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_DescriptorProto_ReservedRange_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_DescriptorProto_ReservedRange_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_ExtensionRangeOptions_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_ExtensionRangeOptions_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_ExtensionRangeOptions_Declaration_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_ExtensionRangeOptions_Declaration_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_FieldDescriptorProto_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_FieldDescriptorProto_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_OneofDescriptorProto_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_OneofDescriptorProto_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_EnumDescriptorProto_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_EnumDescriptorProto_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_EnumDescriptorProto_EnumReservedRange_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_EnumDescriptorProto_EnumReservedRange_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_EnumValueDescriptorProto_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_EnumValueDescriptorProto_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_ServiceDescriptorProto_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_ServiceDescriptorProto_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_MethodDescriptorProto_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_MethodDescriptorProto_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_FileOptions_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_FileOptions_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_MessageOptions_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_MessageOptions_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_FieldOptions_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_FieldOptions_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_FieldOptions_EditionDefault_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_FieldOptions_EditionDefault_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_FieldOptions_FeatureSupport_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_FieldOptions_FeatureSupport_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_OneofOptions_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_OneofOptions_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_EnumOptions_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_EnumOptions_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_EnumValueOptions_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_EnumValueOptions_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_ServiceOptions_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_ServiceOptions_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_MethodOptions_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_MethodOptions_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_UninterpretedOption_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_UninterpretedOption_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_UninterpretedOption_NamePart_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_UninterpretedOption_NamePart_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_FeatureSet_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_FeatureSet_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_FeatureSetDefaults_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_FeatureSetDefaults_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_FeatureSetDefaults_FeatureSetEditionDefault_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_FeatureSetDefaults_FeatureSetEditionDefault_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_SourceCodeInfo_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_SourceCodeInfo_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_SourceCodeInfo_Location_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_SourceCodeInfo_Location_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_GeneratedCodeInfo_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_GeneratedCodeInfo_fieldAccessorTable;
   private static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_GeneratedCodeInfo_Annotation_descriptor;
   private static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_GeneratedCodeInfo_Annotation_fieldAccessorTable;
 
   public static com.google.protobuf.Descriptors.FileDescriptor
@@ -59523,199 +59523,199 @@ public com.google.protobuf.DescriptorProtos.GeneratedCodeInfo getDefaultInstance
     internal_static_google_protobuf_FileDescriptorSet_descriptor =
       getDescriptor().getMessageTypes().get(0);
     internal_static_google_protobuf_FileDescriptorSet_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_FileDescriptorSet_descriptor,
         new java.lang.String[] { "File", });
     internal_static_google_protobuf_FileDescriptorProto_descriptor =
       getDescriptor().getMessageTypes().get(1);
     internal_static_google_protobuf_FileDescriptorProto_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_FileDescriptorProto_descriptor,
         new java.lang.String[] { "Name", "Package", "Dependency", "PublicDependency", "WeakDependency", "MessageType", "EnumType", "Service", "Extension", "Options", "SourceCodeInfo", "Syntax", "Edition", });
     internal_static_google_protobuf_DescriptorProto_descriptor =
       getDescriptor().getMessageTypes().get(2);
     internal_static_google_protobuf_DescriptorProto_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_DescriptorProto_descriptor,
         new java.lang.String[] { "Name", "Field", "Extension", "NestedType", "EnumType", "ExtensionRange", "OneofDecl", "Options", "ReservedRange", "ReservedName", });
     internal_static_google_protobuf_DescriptorProto_ExtensionRange_descriptor =
       internal_static_google_protobuf_DescriptorProto_descriptor.getNestedTypes().get(0);
     internal_static_google_protobuf_DescriptorProto_ExtensionRange_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_DescriptorProto_ExtensionRange_descriptor,
         new java.lang.String[] { "Start", "End", "Options", });
     internal_static_google_protobuf_DescriptorProto_ReservedRange_descriptor =
       internal_static_google_protobuf_DescriptorProto_descriptor.getNestedTypes().get(1);
     internal_static_google_protobuf_DescriptorProto_ReservedRange_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_DescriptorProto_ReservedRange_descriptor,
         new java.lang.String[] { "Start", "End", });
     internal_static_google_protobuf_ExtensionRangeOptions_descriptor =
       getDescriptor().getMessageTypes().get(3);
     internal_static_google_protobuf_ExtensionRangeOptions_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_ExtensionRangeOptions_descriptor,
         new java.lang.String[] { "UninterpretedOption", "Declaration", "Features", "Verification", });
     internal_static_google_protobuf_ExtensionRangeOptions_Declaration_descriptor =
       internal_static_google_protobuf_ExtensionRangeOptions_descriptor.getNestedTypes().get(0);
     internal_static_google_protobuf_ExtensionRangeOptions_Declaration_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_ExtensionRangeOptions_Declaration_descriptor,
         new java.lang.String[] { "Number", "FullName", "Type", "Reserved", "Repeated", });
     internal_static_google_protobuf_FieldDescriptorProto_descriptor =
       getDescriptor().getMessageTypes().get(4);
     internal_static_google_protobuf_FieldDescriptorProto_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_FieldDescriptorProto_descriptor,
         new java.lang.String[] { "Name", "Number", "Label", "Type", "TypeName", "Extendee", "DefaultValue", "OneofIndex", "JsonName", "Options", "Proto3Optional", });
     internal_static_google_protobuf_OneofDescriptorProto_descriptor =
       getDescriptor().getMessageTypes().get(5);
     internal_static_google_protobuf_OneofDescriptorProto_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_OneofDescriptorProto_descriptor,
         new java.lang.String[] { "Name", "Options", });
     internal_static_google_protobuf_EnumDescriptorProto_descriptor =
       getDescriptor().getMessageTypes().get(6);
     internal_static_google_protobuf_EnumDescriptorProto_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_EnumDescriptorProto_descriptor,
         new java.lang.String[] { "Name", "Value", "Options", "ReservedRange", "ReservedName", });
     internal_static_google_protobuf_EnumDescriptorProto_EnumReservedRange_descriptor =
       internal_static_google_protobuf_EnumDescriptorProto_descriptor.getNestedTypes().get(0);
     internal_static_google_protobuf_EnumDescriptorProto_EnumReservedRange_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_EnumDescriptorProto_EnumReservedRange_descriptor,
         new java.lang.String[] { "Start", "End", });
     internal_static_google_protobuf_EnumValueDescriptorProto_descriptor =
       getDescriptor().getMessageTypes().get(7);
     internal_static_google_protobuf_EnumValueDescriptorProto_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_EnumValueDescriptorProto_descriptor,
         new java.lang.String[] { "Name", "Number", "Options", });
     internal_static_google_protobuf_ServiceDescriptorProto_descriptor =
       getDescriptor().getMessageTypes().get(8);
     internal_static_google_protobuf_ServiceDescriptorProto_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_ServiceDescriptorProto_descriptor,
         new java.lang.String[] { "Name", "Method", "Options", });
     internal_static_google_protobuf_MethodDescriptorProto_descriptor =
       getDescriptor().getMessageTypes().get(9);
     internal_static_google_protobuf_MethodDescriptorProto_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_MethodDescriptorProto_descriptor,
         new java.lang.String[] { "Name", "InputType", "OutputType", "Options", "ClientStreaming", "ServerStreaming", });
     internal_static_google_protobuf_FileOptions_descriptor =
       getDescriptor().getMessageTypes().get(10);
     internal_static_google_protobuf_FileOptions_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_FileOptions_descriptor,
         new java.lang.String[] { "JavaPackage", "JavaOuterClassname", "JavaMultipleFiles", "JavaGenerateEqualsAndHash", "JavaStringCheckUtf8", "OptimizeFor", "GoPackage", "CcGenericServices", "JavaGenericServices", "PyGenericServices", "Deprecated", "CcEnableArenas", "ObjcClassPrefix", "CsharpNamespace", "SwiftPrefix", "PhpClassPrefix", "PhpNamespace", "PhpMetadataNamespace", "RubyPackage", "Features", "UninterpretedOption", });
     internal_static_google_protobuf_MessageOptions_descriptor =
       getDescriptor().getMessageTypes().get(11);
     internal_static_google_protobuf_MessageOptions_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_MessageOptions_descriptor,
         new java.lang.String[] { "MessageSetWireFormat", "NoStandardDescriptorAccessor", "Deprecated", "MapEntry", "DeprecatedLegacyJsonFieldConflicts", "Features", "UninterpretedOption", });
     internal_static_google_protobuf_FieldOptions_descriptor =
       getDescriptor().getMessageTypes().get(12);
     internal_static_google_protobuf_FieldOptions_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_FieldOptions_descriptor,
         new java.lang.String[] { "Ctype", "Packed", "Jstype", "Lazy", "UnverifiedLazy", "Deprecated", "Weak", "DebugRedact", "Retention", "Targets", "EditionDefaults", "Features", "FeatureSupport", "UninterpretedOption", });
     internal_static_google_protobuf_FieldOptions_EditionDefault_descriptor =
       internal_static_google_protobuf_FieldOptions_descriptor.getNestedTypes().get(0);
     internal_static_google_protobuf_FieldOptions_EditionDefault_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_FieldOptions_EditionDefault_descriptor,
         new java.lang.String[] { "Edition", "Value", });
     internal_static_google_protobuf_FieldOptions_FeatureSupport_descriptor =
       internal_static_google_protobuf_FieldOptions_descriptor.getNestedTypes().get(1);
     internal_static_google_protobuf_FieldOptions_FeatureSupport_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_FieldOptions_FeatureSupport_descriptor,
         new java.lang.String[] { "EditionIntroduced", "EditionDeprecated", "DeprecationWarning", "EditionRemoved", });
     internal_static_google_protobuf_OneofOptions_descriptor =
       getDescriptor().getMessageTypes().get(13);
     internal_static_google_protobuf_OneofOptions_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_OneofOptions_descriptor,
         new java.lang.String[] { "Features", "UninterpretedOption", });
     internal_static_google_protobuf_EnumOptions_descriptor =
       getDescriptor().getMessageTypes().get(14);
     internal_static_google_protobuf_EnumOptions_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_EnumOptions_descriptor,
         new java.lang.String[] { "AllowAlias", "Deprecated", "DeprecatedLegacyJsonFieldConflicts", "Features", "UninterpretedOption", });
     internal_static_google_protobuf_EnumValueOptions_descriptor =
       getDescriptor().getMessageTypes().get(15);
     internal_static_google_protobuf_EnumValueOptions_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_EnumValueOptions_descriptor,
         new java.lang.String[] { "Deprecated", "Features", "DebugRedact", "FeatureSupport", "UninterpretedOption", });
     internal_static_google_protobuf_ServiceOptions_descriptor =
       getDescriptor().getMessageTypes().get(16);
     internal_static_google_protobuf_ServiceOptions_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_ServiceOptions_descriptor,
         new java.lang.String[] { "Features", "Deprecated", "UninterpretedOption", });
     internal_static_google_protobuf_MethodOptions_descriptor =
       getDescriptor().getMessageTypes().get(17);
     internal_static_google_protobuf_MethodOptions_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_MethodOptions_descriptor,
         new java.lang.String[] { "Deprecated", "IdempotencyLevel", "Features", "UninterpretedOption", });
     internal_static_google_protobuf_UninterpretedOption_descriptor =
       getDescriptor().getMessageTypes().get(18);
     internal_static_google_protobuf_UninterpretedOption_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_UninterpretedOption_descriptor,
         new java.lang.String[] { "Name", "IdentifierValue", "PositiveIntValue", "NegativeIntValue", "DoubleValue", "StringValue", "AggregateValue", });
     internal_static_google_protobuf_UninterpretedOption_NamePart_descriptor =
       internal_static_google_protobuf_UninterpretedOption_descriptor.getNestedTypes().get(0);
     internal_static_google_protobuf_UninterpretedOption_NamePart_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_UninterpretedOption_NamePart_descriptor,
         new java.lang.String[] { "NamePart", "IsExtension", });
     internal_static_google_protobuf_FeatureSet_descriptor =
       getDescriptor().getMessageTypes().get(19);
     internal_static_google_protobuf_FeatureSet_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_FeatureSet_descriptor,
         new java.lang.String[] { "FieldPresence", "EnumType", "RepeatedFieldEncoding", "Utf8Validation", "MessageEncoding", "JsonFormat", });
     internal_static_google_protobuf_FeatureSetDefaults_descriptor =
       getDescriptor().getMessageTypes().get(20);
     internal_static_google_protobuf_FeatureSetDefaults_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_FeatureSetDefaults_descriptor,
         new java.lang.String[] { "Defaults", "MinimumEdition", "MaximumEdition", });
     internal_static_google_protobuf_FeatureSetDefaults_FeatureSetEditionDefault_descriptor =
       internal_static_google_protobuf_FeatureSetDefaults_descriptor.getNestedTypes().get(0);
     internal_static_google_protobuf_FeatureSetDefaults_FeatureSetEditionDefault_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_FeatureSetDefaults_FeatureSetEditionDefault_descriptor,
         new java.lang.String[] { "Edition", "OverridableFeatures", "FixedFeatures", });
     internal_static_google_protobuf_SourceCodeInfo_descriptor =
       getDescriptor().getMessageTypes().get(21);
     internal_static_google_protobuf_SourceCodeInfo_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_SourceCodeInfo_descriptor,
         new java.lang.String[] { "Location", });
     internal_static_google_protobuf_SourceCodeInfo_Location_descriptor =
       internal_static_google_protobuf_SourceCodeInfo_descriptor.getNestedTypes().get(0);
     internal_static_google_protobuf_SourceCodeInfo_Location_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_SourceCodeInfo_Location_descriptor,
         new java.lang.String[] { "Path", "Span", "LeadingComments", "TrailingComments", "LeadingDetachedComments", });
     internal_static_google_protobuf_GeneratedCodeInfo_descriptor =
       getDescriptor().getMessageTypes().get(22);
     internal_static_google_protobuf_GeneratedCodeInfo_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_GeneratedCodeInfo_descriptor,
         new java.lang.String[] { "Annotation", });
     internal_static_google_protobuf_GeneratedCodeInfo_Annotation_descriptor =
       internal_static_google_protobuf_GeneratedCodeInfo_descriptor.getNestedTypes().get(0);
     internal_static_google_protobuf_GeneratedCodeInfo_Annotation_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_GeneratedCodeInfo_Annotation_descriptor,
         new java.lang.String[] { "Path", "SourceFile", "Begin", "End", "Semantic", });
   }
diff --git a/protobuf-api/src/main/java/com/google/protobuf/Descriptors.java b/protobuf-api/src/main/java/com/google/protobuf/Descriptors.java
index fb9b661..23d43aa 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/Descriptors.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/Descriptors.java
@@ -1649,20 +1649,20 @@ private void crossLink() throws DescriptorValidationException {
             case INT32:
             case SINT32:
             case SFIXED32:
-              defaultValue = TextFormat.parseInt32(proto.getDefaultValue());
+              defaultValue = TextFormatInternal.parseInt32(proto.getDefaultValue());
               break;
             case UINT32:
             case FIXED32:
-              defaultValue = TextFormat.parseUInt32(proto.getDefaultValue());
+              defaultValue = TextFormatInternal.parseUInt32(proto.getDefaultValue());
               break;
             case INT64:
             case SINT64:
             case SFIXED64:
-              defaultValue = TextFormat.parseInt64(proto.getDefaultValue());
+              defaultValue = TextFormatInternal.parseInt64(proto.getDefaultValue());
               break;
             case UINT64:
             case FIXED64:
-              defaultValue = TextFormat.parseUInt64(proto.getDefaultValue());
+              defaultValue = TextFormatInternal.parseUInt64(proto.getDefaultValue());
               break;
             case FLOAT:
               if (proto.getDefaultValue().equals("inf")) {
@@ -1694,8 +1694,8 @@ private void crossLink() throws DescriptorValidationException {
               break;
             case BYTES:
               try {
-                defaultValue = TextFormat.unescapeBytes(proto.getDefaultValue());
-              } catch (TextFormat.InvalidEscapeSequenceException e) {
+                defaultValue = TextFormatEscaper.unescapeBytes(proto.getDefaultValue());
+              } catch (Exception e) {
                 throw new DescriptorValidationException(
                     this, "Couldn't parse default value: " + e.getMessage(), e);
               }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/DoubleValue.java b/protobuf-api/src/main/java/com/google/protobuf/DoubleValue.java
similarity index 94%
rename from protobuf-sdk/src/main/java/com/google/protobuf/DoubleValue.java
rename to protobuf-api/src/main/java/com/google/protobuf/DoubleValue.java
index 974047a..725a829 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/DoubleValue.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/DoubleValue.java
@@ -14,12 +14,12 @@
  * Protobuf type {@code google.protobuf.DoubleValue}
  */
 public final class DoubleValue extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.DoubleValue)
     DoubleValueOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use DoubleValue.newBuilder() to construct.
-  private DoubleValue(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private DoubleValue(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private DoubleValue() {
@@ -38,7 +38,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.WrappersProto.internal_static_google_protobuf_DoubleValue_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -161,20 +161,20 @@ public static com.google.protobuf.DoubleValue parseFrom(
   }
   public static com.google.protobuf.DoubleValue parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.DoubleValue parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.DoubleValue parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -182,20 +182,20 @@ public static com.google.protobuf.DoubleValue parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.DoubleValue parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.DoubleValue parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -215,7 +215,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -229,7 +229,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.DoubleValue}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.DoubleValue)
       com.google.protobuf.DoubleValueOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -238,7 +238,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.WrappersProto.internal_static_google_protobuf_DoubleValue_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -251,7 +251,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/DoubleValueOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/DoubleValueOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/DoubleValueOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/DoubleValueOrBuilder.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/Duration.java b/protobuf-api/src/main/java/com/google/protobuf/Duration.java
similarity index 96%
rename from protobuf-sdk/src/main/java/com/google/protobuf/Duration.java
rename to protobuf-api/src/main/java/com/google/protobuf/Duration.java
index b0679c0..13cdf17 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/Duration.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/Duration.java
@@ -69,12 +69,12 @@
  * Protobuf type {@code google.protobuf.Duration}
  */
 public final class Duration extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.Duration)
     DurationOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use Duration.newBuilder() to construct.
-  private Duration(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private Duration(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private Duration() {
@@ -93,7 +93,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.DurationProto.internal_static_google_protobuf_Duration_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -248,20 +248,20 @@ public static com.google.protobuf.Duration parseFrom(
   }
   public static com.google.protobuf.Duration parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Duration parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.Duration parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -269,20 +269,20 @@ public static com.google.protobuf.Duration parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.Duration parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Duration parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -302,7 +302,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -371,7 +371,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.Duration}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.Duration)
       com.google.protobuf.DurationOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -380,7 +380,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.DurationProto.internal_static_google_protobuf_Duration_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -393,7 +393,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/DurationOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/DurationOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/DurationOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/DurationOrBuilder.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/DurationProto.java b/protobuf-api/src/main/java/com/google/protobuf/DurationProto.java
similarity index 93%
rename from protobuf-sdk/src/main/java/com/google/protobuf/DurationProto.java
rename to protobuf-api/src/main/java/com/google/protobuf/DurationProto.java
index cd13d21..7deb34e 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/DurationProto.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/DurationProto.java
@@ -18,7 +18,7 @@ public static void registerAllExtensions(
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_Duration_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_Duration_fieldAccessorTable;
 
   public static com.google.protobuf.Descriptors.FileDescriptor
@@ -43,7 +43,7 @@ public static void registerAllExtensions(
     internal_static_google_protobuf_Duration_descriptor =
       getDescriptor().getMessageTypes().get(0);
     internal_static_google_protobuf_Duration_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_Duration_descriptor,
         new java.lang.String[] { "Seconds", "Nanos", });
   }
diff --git a/protobuf-api/src/main/java/com/google/protobuf/DynamicMessage.java b/protobuf-api/src/main/java/com/google/protobuf/DynamicMessage.java
index de98df0..578e362 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/DynamicMessage.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/DynamicMessage.java
@@ -26,7 +26,7 @@
  *
  * @author kenton@google.com Kenton Varda
  */
-public final class DynamicMessage extends AbstractMessage {
+public final class DynamicMessage extends FlattenedAbstractMessage {
   private final Descriptor type;
   private final FieldSet<FieldDescriptor> fields;
   private final FieldDescriptor[] oneofCases;
@@ -293,7 +293,7 @@ private void verifyOneofContainingType(OneofDescriptor oneof) {
   // =================================================================
 
   /** Builder for {@link DynamicMessage}s. */
-  public static final class Builder extends AbstractMessage.Builder<Builder> {
+  public static final class Builder extends FlattenedAbstractMessage.Builder<Builder> {
     private final Descriptor type;
     private FieldSet.Builder<FieldDescriptor> fields;
     private final FieldDescriptor[] oneofCases;
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/Empty.java b/protobuf-api/src/main/java/com/google/protobuf/Empty.java
similarity index 93%
rename from protobuf-sdk/src/main/java/com/google/protobuf/Empty.java
rename to protobuf-api/src/main/java/com/google/protobuf/Empty.java
index 04437a3..7b58465 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/Empty.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/Empty.java
@@ -18,12 +18,12 @@
  * Protobuf type {@code google.protobuf.Empty}
  */
 public final class Empty extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.Empty)
     EmptyOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use Empty.newBuilder() to construct.
-  private Empty(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private Empty(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private Empty() {
@@ -42,7 +42,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.EmptyProto.internal_static_google_protobuf_Empty_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -137,20 +137,20 @@ public static com.google.protobuf.Empty parseFrom(
   }
   public static com.google.protobuf.Empty parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Empty parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.Empty parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -158,20 +158,20 @@ public static com.google.protobuf.Empty parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.Empty parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Empty parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -191,7 +191,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -209,7 +209,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.Empty}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.Empty)
       com.google.protobuf.EmptyOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -218,7 +218,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.EmptyProto.internal_static_google_protobuf_Empty_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -231,7 +231,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/EmptyOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/EmptyOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/EmptyOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/EmptyOrBuilder.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/EmptyProto.java b/protobuf-api/src/main/java/com/google/protobuf/EmptyProto.java
similarity index 92%
rename from protobuf-sdk/src/main/java/com/google/protobuf/EmptyProto.java
rename to protobuf-api/src/main/java/com/google/protobuf/EmptyProto.java
index 666acb2..6c4ee36 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/EmptyProto.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/EmptyProto.java
@@ -18,7 +18,7 @@ public static void registerAllExtensions(
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_Empty_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_Empty_fieldAccessorTable;
 
   public static com.google.protobuf.Descriptors.FileDescriptor
@@ -42,7 +42,7 @@ public static void registerAllExtensions(
     internal_static_google_protobuf_Empty_descriptor =
       getDescriptor().getMessageTypes().get(0);
     internal_static_google_protobuf_Empty_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_Empty_descriptor,
         new java.lang.String[] { });
   }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/Enum.java b/protobuf-api/src/main/java/com/google/protobuf/Enum.java
similarity index 94%
rename from protobuf-sdk/src/main/java/com/google/protobuf/Enum.java
rename to protobuf-api/src/main/java/com/google/protobuf/Enum.java
index 17f3bf8..e4c44b1 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/Enum.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/Enum.java
@@ -12,12 +12,12 @@
  * Protobuf type {@code google.protobuf.Enum}
  */
 public final class Enum extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.Enum)
     EnumOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use Enum.newBuilder() to construct.
-  private Enum(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private Enum(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private Enum() {
@@ -41,7 +41,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.TypeProto.internal_static_google_protobuf_Enum_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -343,8 +343,8 @@ public final boolean isInitialized() {
   @java.lang.Override
   public void writeTo(com.google.protobuf.CodedOutputStream output)
                       throws java.io.IOException {
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 1, name_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(name_)) {
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, name_);
     }
     for (int i = 0; i < enumvalue_.size(); i++) {
       output.writeMessage(2, enumvalue_.get(i));
@@ -358,8 +358,8 @@ public void writeTo(com.google.protobuf.CodedOutputStream output)
     if (syntax_ != com.google.protobuf.Syntax.SYNTAX_PROTO2.getNumber()) {
       output.writeEnum(5, syntax_);
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(edition_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 6, edition_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(edition_)) {
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 6, edition_);
     }
     getUnknownFields().writeTo(output);
   }
@@ -370,8 +370,8 @@ public int getSerializedSize() {
     if (size != -1) return size;
 
     size = 0;
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, name_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(name_)) {
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(1, name_);
     }
     for (int i = 0; i < enumvalue_.size(); i++) {
       size += com.google.protobuf.CodedOutputStream
@@ -389,8 +389,8 @@ public int getSerializedSize() {
       size += com.google.protobuf.CodedOutputStream
         .computeEnumSize(5, syntax_);
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(edition_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(6, edition_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(edition_)) {
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(6, edition_);
     }
     size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
@@ -489,20 +489,20 @@ public static com.google.protobuf.Enum parseFrom(
   }
   public static com.google.protobuf.Enum parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Enum parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.Enum parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -510,20 +510,20 @@ public static com.google.protobuf.Enum parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.Enum parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Enum parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -543,7 +543,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -555,7 +555,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.Enum}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.Enum)
       com.google.protobuf.EnumOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -564,7 +564,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.TypeProto.internal_static_google_protobuf_Enum_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -577,12 +577,12 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
       maybeForceBuilderInitialization();
     }
     private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3
+      if (com.google.protobuf.GeneratedMessageV3Internal
               .alwaysUseFieldBuilders) {
         getEnumvalueFieldBuilder();
         getOptionsFieldBuilder();
@@ -757,7 +757,7 @@ public Builder mergeFrom(com.google.protobuf.Enum other) {
             enumvalue_ = other.enumvalue_;
             bitField0_ = (bitField0_ & ~0x00000002);
             enumvalueBuilder_ = 
-              com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+              com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                  getEnumvalueFieldBuilder() : null;
           } else {
             enumvalueBuilder_.addAllMessages(other.enumvalue_);
@@ -783,7 +783,7 @@ public Builder mergeFrom(com.google.protobuf.Enum other) {
             options_ = other.options_;
             bitField0_ = (bitField0_ & ~0x00000004);
             optionsBuilder_ = 
-              com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+              com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                  getOptionsFieldBuilder() : null;
           } else {
             optionsBuilder_.addAllMessages(other.options_);
@@ -993,8 +993,8 @@ private void ensureEnumvalueIsMutable() {
        }
     }
 
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.EnumValue, com.google.protobuf.EnumValue.Builder, com.google.protobuf.EnumValueOrBuilder> enumvalueBuilder_;
+    private RepeatedFieldBuilderV3Internal<
+            EnumValue, EnumValue.Builder, EnumValueOrBuilder> enumvalueBuilder_;
 
     /**
      * <pre>
@@ -1281,12 +1281,12 @@ public com.google.protobuf.EnumValue.Builder addEnumvalueBuilder(
          getEnumvalueBuilderList() {
       return getEnumvalueFieldBuilder().getBuilderList();
     }
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.EnumValue, com.google.protobuf.EnumValue.Builder, com.google.protobuf.EnumValueOrBuilder> 
+    private RepeatedFieldBuilderV3Internal<
+            EnumValue, EnumValue.Builder, EnumValueOrBuilder>
         getEnumvalueFieldBuilder() {
       if (enumvalueBuilder_ == null) {
-        enumvalueBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-            com.google.protobuf.EnumValue, com.google.protobuf.EnumValue.Builder, com.google.protobuf.EnumValueOrBuilder>(
+        enumvalueBuilder_ = new RepeatedFieldBuilderV3Internal<
+                    EnumValue, EnumValue.Builder, EnumValueOrBuilder>(
                 enumvalue_,
                 ((bitField0_ & 0x00000002) != 0),
                 getParentForChildren(),
@@ -1305,8 +1305,8 @@ private void ensureOptionsIsMutable() {
        }
     }
 
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Option, com.google.protobuf.Option.Builder, com.google.protobuf.OptionOrBuilder> optionsBuilder_;
+    private RepeatedFieldBuilderV3Internal<
+            Option, Option.Builder, OptionOrBuilder> optionsBuilder_;
 
     /**
      * <pre>
@@ -1593,12 +1593,12 @@ public com.google.protobuf.Option.Builder addOptionsBuilder(
          getOptionsBuilderList() {
       return getOptionsFieldBuilder().getBuilderList();
     }
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Option, com.google.protobuf.Option.Builder, com.google.protobuf.OptionOrBuilder> 
+    private RepeatedFieldBuilderV3Internal<
+            Option, Option.Builder, OptionOrBuilder>
         getOptionsFieldBuilder() {
       if (optionsBuilder_ == null) {
-        optionsBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-            com.google.protobuf.Option, com.google.protobuf.Option.Builder, com.google.protobuf.OptionOrBuilder>(
+        optionsBuilder_ = new RepeatedFieldBuilderV3Internal<
+                    Option, Option.Builder, OptionOrBuilder>(
                 options_,
                 ((bitField0_ & 0x00000004) != 0),
                 getParentForChildren(),
@@ -1609,8 +1609,8 @@ public com.google.protobuf.Option.Builder addOptionsBuilder(
     }
 
     private com.google.protobuf.SourceContext sourceContext_;
-    private com.google.protobuf.SingleFieldBuilderV3<
-        com.google.protobuf.SourceContext, com.google.protobuf.SourceContext.Builder, com.google.protobuf.SourceContextOrBuilder> sourceContextBuilder_;
+    private SingleFieldBuilderV3Internal<
+            SourceContext, SourceContext.Builder, SourceContextOrBuilder> sourceContextBuilder_;
     /**
      * <pre>
      * The source context.
@@ -1751,12 +1751,12 @@ public com.google.protobuf.SourceContextOrBuilder getSourceContextOrBuilder() {
      *
      * <code>.google.protobuf.SourceContext source_context = 4;</code>
      */
-    private com.google.protobuf.SingleFieldBuilderV3<
-        com.google.protobuf.SourceContext, com.google.protobuf.SourceContext.Builder, com.google.protobuf.SourceContextOrBuilder> 
+    private SingleFieldBuilderV3Internal<
+            SourceContext, SourceContext.Builder, SourceContextOrBuilder>
         getSourceContextFieldBuilder() {
       if (sourceContextBuilder_ == null) {
-        sourceContextBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-            com.google.protobuf.SourceContext, com.google.protobuf.SourceContext.Builder, com.google.protobuf.SourceContextOrBuilder>(
+        sourceContextBuilder_ = new SingleFieldBuilderV3Internal<
+                    SourceContext, SourceContext.Builder, SourceContextOrBuilder>(
                 getSourceContext(),
                 getParentForChildren(),
                 isClean());
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/EnumOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/EnumOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/EnumOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/EnumOrBuilder.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/EnumValue.java b/protobuf-api/src/main/java/com/google/protobuf/EnumValue.java
similarity index 94%
rename from protobuf-sdk/src/main/java/com/google/protobuf/EnumValue.java
rename to protobuf-api/src/main/java/com/google/protobuf/EnumValue.java
index 62634f4..41c3bf9 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/EnumValue.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/EnumValue.java
@@ -12,12 +12,12 @@
  * Protobuf type {@code google.protobuf.EnumValue}
  */
 public final class EnumValue extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.EnumValue)
     EnumValueOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use EnumValue.newBuilder() to construct.
-  private EnumValue(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private EnumValue(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private EnumValue() {
@@ -38,7 +38,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.TypeProto.internal_static_google_protobuf_EnumValue_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -182,8 +182,8 @@ public final boolean isInitialized() {
   @java.lang.Override
   public void writeTo(com.google.protobuf.CodedOutputStream output)
                       throws java.io.IOException {
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 1, name_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(name_)) {
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, name_);
     }
     if (number_ != 0) {
       output.writeInt32(2, number_);
@@ -200,8 +200,8 @@ public int getSerializedSize() {
     if (size != -1) return size;
 
     size = 0;
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, name_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(name_)) {
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(1, name_);
     }
     if (number_ != 0) {
       size += com.google.protobuf.CodedOutputStream
@@ -290,20 +290,20 @@ public static com.google.protobuf.EnumValue parseFrom(
   }
   public static com.google.protobuf.EnumValue parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.EnumValue parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.EnumValue parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -311,20 +311,20 @@ public static com.google.protobuf.EnumValue parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.EnumValue parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.EnumValue parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -344,7 +344,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -356,7 +356,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.EnumValue}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.EnumValue)
       com.google.protobuf.EnumValueOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -365,7 +365,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.TypeProto.internal_static_google_protobuf_EnumValue_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -378,7 +378,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
@@ -520,7 +520,7 @@ public Builder mergeFrom(com.google.protobuf.EnumValue other) {
             options_ = other.options_;
             bitField0_ = (bitField0_ & ~0x00000004);
             optionsBuilder_ = 
-              com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+              com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                  getOptionsFieldBuilder() : null;
           } else {
             optionsBuilder_.addAllMessages(other.options_);
@@ -738,8 +738,8 @@ private void ensureOptionsIsMutable() {
        }
     }
 
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Option, com.google.protobuf.Option.Builder, com.google.protobuf.OptionOrBuilder> optionsBuilder_;
+    private RepeatedFieldBuilderV3Internal<
+            Option, Option.Builder, OptionOrBuilder> optionsBuilder_;
 
     /**
      * <pre>
@@ -1026,12 +1026,12 @@ public com.google.protobuf.Option.Builder addOptionsBuilder(
          getOptionsBuilderList() {
       return getOptionsFieldBuilder().getBuilderList();
     }
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Option, com.google.protobuf.Option.Builder, com.google.protobuf.OptionOrBuilder> 
+    private RepeatedFieldBuilderV3Internal<
+            Option, Option.Builder, OptionOrBuilder>
         getOptionsFieldBuilder() {
       if (optionsBuilder_ == null) {
-        optionsBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-            com.google.protobuf.Option, com.google.protobuf.Option.Builder, com.google.protobuf.OptionOrBuilder>(
+        optionsBuilder_ = new RepeatedFieldBuilderV3Internal<
+                    Option, Option.Builder, OptionOrBuilder>(
                 options_,
                 ((bitField0_ & 0x00000004) != 0),
                 getParentForChildren(),
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/EnumValueOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/EnumValueOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/EnumValueOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/EnumValueOrBuilder.java
diff --git a/protobuf-api/src/main/java/com/google/protobuf/ExtensionRegistry.java b/protobuf-api/src/main/java/com/google/protobuf/ExtensionRegistry.java
index 39babd3..665eee4 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/ExtensionRegistry.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/ExtensionRegistry.java
@@ -200,10 +200,11 @@ public void add(final Extension<?, ?> extension) {
     add(newExtensionInfo(extension), extension.getExtensionType());
   }
 
-  /** Add an extension from a generated file to the registry. */
-  public void add(final GeneratedMessage.GeneratedExtension<?, ?> extension) {
-    add((Extension<?, ?>) extension);
-  }
+  //This method should be deprecated and then removed.
+//  /** Add an extension from a generated file to the registry. */
+//  public void add(final GeneratedMessage.GeneratedExtension<?, ?> extension) {
+//    add((Extension<?, ?>) extension);
+//  }
 
   static ExtensionInfo newExtensionInfo(final Extension<?, ?> extension) {
     if (extension.getDescriptor().getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
diff --git a/protobuf-api/src/main/java/com/google/protobuf/ExtensionRegistryLite.java b/protobuf-api/src/main/java/com/google/protobuf/ExtensionRegistryLite.java
index 18d14bf..0bd38f6 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/ExtensionRegistryLite.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/ExtensionRegistryLite.java
@@ -7,6 +7,7 @@
 
 package com.google.protobuf;
 
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
@@ -127,17 +128,17 @@ public ExtensionRegistryLite getUnmodifiable() {
    */
   @SuppressWarnings("unchecked")
   public <ContainingType extends MessageLite>
-      GeneratedMessageLite.GeneratedExtension<ContainingType, ?> findLiteExtensionByNumber(
+  GeneratedMessageLite.GeneratedExtension<ContainingType, ?> findLiteExtensionByNumber(
           final ContainingType containingTypeDefaultInstance, final int fieldNumber) {
     return (GeneratedMessageLite.GeneratedExtension<ContainingType, ?>)
-        extensionsByNumber.get(new ObjectIntPair(containingTypeDefaultInstance, fieldNumber));
+            extensionsByNumber.get(new ObjectIntPair(containingTypeDefaultInstance, fieldNumber));
   }
 
   /** Add an extension from a lite generated file to the registry. */
   public final void add(final GeneratedMessageLite.GeneratedExtension<?, ?> extension) {
     extensionsByNumber.put(
-        new ObjectIntPair(extension.getContainingTypeDefaultInstance(), extension.getNumber()),
-        extension);
+            new ObjectIntPair(extension.getContainingTypeDefaultInstance(), extension.getNumber()),
+            extension);
   }
 
   /**
@@ -153,7 +154,7 @@ public final void add(ExtensionLite<?, ?> extension) {
         this.getClass().getMethod("add", ExtensionClassHolder.INSTANCE).invoke(this, extension);
       } catch (Exception e) {
         throw new IllegalArgumentException(
-            String.format("Could not invoke ExtensionRegistry#add for %s", extension), e);
+                String.format("Could not invoke ExtensionRegistry#add for %s", extension), e);
       }
     }
   }
@@ -166,7 +167,7 @@ public final void add(ExtensionLite<?, ?> extension) {
 
   ExtensionRegistryLite() {
     this.extensionsByNumber =
-        new HashMap<ObjectIntPair, GeneratedMessageLite.GeneratedExtension<?, ?>>();
+        new HashMap<ObjectIntPair, ExtensionLite<?, ?>>();
   }
 
   static final ExtensionRegistryLite EMPTY_REGISTRY_LITE = new ExtensionRegistryLite(true);
@@ -179,7 +180,7 @@ public final void add(ExtensionLite<?, ?> extension) {
     }
   }
 
-  private final Map<ObjectIntPair, GeneratedMessageLite.GeneratedExtension<?, ?>>
+  private final Map<ObjectIntPair, ExtensionLite<?, ?>>
       extensionsByNumber;
 
   ExtensionRegistryLite(boolean empty) {
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/Field.java b/protobuf-api/src/main/java/com/google/protobuf/Field.java
similarity index 96%
rename from protobuf-sdk/src/main/java/com/google/protobuf/Field.java
rename to protobuf-api/src/main/java/com/google/protobuf/Field.java
index 0cd180b..566c163 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/Field.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/Field.java
@@ -12,12 +12,12 @@
  * Protobuf type {@code google.protobuf.Field}
  */
 public final class Field extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.Field)
     FieldOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use Field.newBuilder() to construct.
-  private Field(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private Field(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private Field() {
@@ -43,7 +43,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.TypeProto.internal_static_google_protobuf_Field_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -1001,11 +1001,11 @@ public void writeTo(com.google.protobuf.CodedOutputStream output)
     if (number_ != 0) {
       output.writeInt32(3, number_);
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 4, name_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(name_)) {
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 4, name_);
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(typeUrl_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 6, typeUrl_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(typeUrl_)) {
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 6, typeUrl_);
     }
     if (oneofIndex_ != 0) {
       output.writeInt32(7, oneofIndex_);
@@ -1016,11 +1016,11 @@ public void writeTo(com.google.protobuf.CodedOutputStream output)
     for (int i = 0; i < options_.size(); i++) {
       output.writeMessage(9, options_.get(i));
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(jsonName_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 10, jsonName_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(jsonName_)) {
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 10, jsonName_);
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(defaultValue_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 11, defaultValue_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(defaultValue_)) {
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 11, defaultValue_);
     }
     getUnknownFields().writeTo(output);
   }
@@ -1043,11 +1043,11 @@ public int getSerializedSize() {
       size += com.google.protobuf.CodedOutputStream
         .computeInt32Size(3, number_);
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(4, name_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(name_)) {
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(4, name_);
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(typeUrl_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(6, typeUrl_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(typeUrl_)) {
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(6, typeUrl_);
     }
     if (oneofIndex_ != 0) {
       size += com.google.protobuf.CodedOutputStream
@@ -1061,11 +1061,11 @@ public int getSerializedSize() {
       size += com.google.protobuf.CodedOutputStream
         .computeMessageSize(9, options_.get(i));
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(jsonName_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(10, jsonName_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(jsonName_)) {
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(10, jsonName_);
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(defaultValue_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(11, defaultValue_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(defaultValue_)) {
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(11, defaultValue_);
     }
     size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
@@ -1173,20 +1173,20 @@ public static com.google.protobuf.Field parseFrom(
   }
   public static com.google.protobuf.Field parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Field parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.Field parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -1194,20 +1194,20 @@ public static com.google.protobuf.Field parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.Field parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Field parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -1227,7 +1227,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -1239,7 +1239,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.Field}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.Field)
       com.google.protobuf.FieldOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -1248,7 +1248,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.TypeProto.internal_static_google_protobuf_Field_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -1261,7 +1261,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
@@ -1448,7 +1448,7 @@ public Builder mergeFrom(com.google.protobuf.Field other) {
             options_ = other.options_;
             bitField0_ = (bitField0_ & ~0x00000080);
             optionsBuilder_ = 
-              com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+              com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                  getOptionsFieldBuilder() : null;
           } else {
             optionsBuilder_.addAllMessages(other.options_);
@@ -2045,8 +2045,8 @@ private void ensureOptionsIsMutable() {
        }
     }
 
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Option, com.google.protobuf.Option.Builder, com.google.protobuf.OptionOrBuilder> optionsBuilder_;
+    private RepeatedFieldBuilderV3Internal<
+            Option, Option.Builder, OptionOrBuilder> optionsBuilder_;
 
     /**
      * <pre>
@@ -2333,12 +2333,12 @@ public com.google.protobuf.Option.Builder addOptionsBuilder(
          getOptionsBuilderList() {
       return getOptionsFieldBuilder().getBuilderList();
     }
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Option, com.google.protobuf.Option.Builder, com.google.protobuf.OptionOrBuilder> 
+    private RepeatedFieldBuilderV3Internal<
+            Option, Option.Builder, OptionOrBuilder>
         getOptionsFieldBuilder() {
       if (optionsBuilder_ == null) {
-        optionsBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-            com.google.protobuf.Option, com.google.protobuf.Option.Builder, com.google.protobuf.OptionOrBuilder>(
+        optionsBuilder_ = new RepeatedFieldBuilderV3Internal<
+                    Option, Option.Builder, OptionOrBuilder>(
                 options_,
                 ((bitField0_ & 0x00000080) != 0),
                 getParentForChildren(),
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/FieldMask.java b/protobuf-api/src/main/java/com/google/protobuf/FieldMask.java
similarity index 96%
rename from protobuf-sdk/src/main/java/com/google/protobuf/FieldMask.java
rename to protobuf-api/src/main/java/com/google/protobuf/FieldMask.java
index 5aab429..e96c5f9 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/FieldMask.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/FieldMask.java
@@ -210,12 +210,12 @@
  * Protobuf type {@code google.protobuf.FieldMask}
  */
 public final class FieldMask extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.FieldMask)
     FieldMaskOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use FieldMask.newBuilder() to construct.
-  private FieldMask(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private FieldMask(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private FieldMask() {
@@ -236,7 +236,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.FieldMaskProto.internal_static_google_protobuf_FieldMask_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -311,7 +311,7 @@ public final boolean isInitialized() {
   public void writeTo(com.google.protobuf.CodedOutputStream output)
                       throws java.io.IOException {
     for (int i = 0; i < paths_.size(); i++) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 1, paths_.getRaw(i));
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, paths_.getRaw(i));
     }
     getUnknownFields().writeTo(output);
   }
@@ -401,20 +401,20 @@ public static com.google.protobuf.FieldMask parseFrom(
   }
   public static com.google.protobuf.FieldMask parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.FieldMask parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.FieldMask parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -422,20 +422,20 @@ public static com.google.protobuf.FieldMask parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.FieldMask parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.FieldMask parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -455,7 +455,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -665,7 +665,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.FieldMask}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.FieldMask)
       com.google.protobuf.FieldMaskOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -674,7 +674,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.FieldMaskProto.internal_static_google_protobuf_FieldMask_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -687,7 +687,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/FieldMaskOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/FieldMaskOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/FieldMaskOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/FieldMaskOrBuilder.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/FieldMaskProto.java b/protobuf-api/src/main/java/com/google/protobuf/FieldMaskProto.java
similarity index 92%
rename from protobuf-sdk/src/main/java/com/google/protobuf/FieldMaskProto.java
rename to protobuf-api/src/main/java/com/google/protobuf/FieldMaskProto.java
index cfc5499..396e60c 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/FieldMaskProto.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/FieldMaskProto.java
@@ -18,7 +18,7 @@ public static void registerAllExtensions(
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_FieldMask_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_FieldMask_fieldAccessorTable;
 
   public static com.google.protobuf.Descriptors.FileDescriptor
@@ -43,7 +43,7 @@ public static void registerAllExtensions(
     internal_static_google_protobuf_FieldMask_descriptor =
       getDescriptor().getMessageTypes().get(0);
     internal_static_google_protobuf_FieldMask_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_FieldMask_descriptor,
         new java.lang.String[] { "Paths", });
   }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/FieldOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/FieldOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/FieldOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/FieldOrBuilder.java
diff --git a/protobuf-api/src/main/java/com/google/protobuf/FlattenedAbstractMessage.java b/protobuf-api/src/main/java/com/google/protobuf/FlattenedAbstractMessage.java
new file mode 100644
index 0000000..c5542d2
--- /dev/null
+++ b/protobuf-api/src/main/java/com/google/protobuf/FlattenedAbstractMessage.java
@@ -0,0 +1,841 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+
+package com.google.protobuf;
+
+import com.google.protobuf.Descriptors.EnumValueDescriptor;
+import com.google.protobuf.Descriptors.FieldDescriptor;
+import com.google.protobuf.Descriptors.OneofDescriptor;
+import com.google.protobuf.Internal.EnumLite;
+
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+
+import static com.google.protobuf.Internal.checkNotNull;
+
+/**
+ * A partial implementation of the {@link Message} interface which implements as many methods of
+ * that interface as possible in terms of other methods.
+ *
+ * @author kenton@google.com Kenton Varda
+ */
+public abstract class FlattenedAbstractMessage
+    // TODO: Update GeneratedMessage to parameterize with MessageType and BuilderType.
+ implements Message {
+
+  protected int memoizedHashCode = 0;
+
+  @Override
+  public ByteString toByteString() {
+    try {
+      final ByteString.CodedBuilder out = ByteString.newCodedBuilder(getSerializedSize());
+      writeTo(out.getCodedOutput());
+      return out.build();
+    } catch (IOException e) {
+      throw new RuntimeException(getSerializingExceptionMessage("ByteString"), e);
+    }
+  }
+
+  @Override
+  public byte[] toByteArray() {
+    try {
+      final byte[] result = new byte[getSerializedSize()];
+      final CodedOutputStream output = CodedOutputStream.newInstance(result);
+      writeTo(output);
+      output.checkNoSpaceLeft();
+      return result;
+    } catch (IOException e) {
+      throw new RuntimeException(getSerializingExceptionMessage("byte array"), e);
+    }
+  }
+
+  @Override
+  public void writeTo(final OutputStream output) throws IOException {
+    final int bufferSize = CodedOutputStream.computePreferredBufferSize(getSerializedSize());
+    final CodedOutputStream codedOutput = CodedOutputStream.newInstance(output, bufferSize);
+    writeTo(codedOutput);
+    codedOutput.flush();
+  }
+
+  @Override
+  public void writeDelimitedTo(final OutputStream output) throws IOException {
+    final int serialized = getSerializedSize();
+    final int bufferSize =
+            CodedOutputStream.computePreferredBufferSize(
+                    CodedOutputStream.computeUInt32SizeNoTag(serialized) + serialized);
+    final CodedOutputStream codedOutput = CodedOutputStream.newInstance(output, bufferSize);
+    codedOutput.writeUInt32NoTag(serialized);
+    writeTo(codedOutput);
+    codedOutput.flush();
+  }
+
+  int getSerializedSize(
+          Schema schema) {
+    int memoizedSerializedSize = getMemoizedSerializedSize();
+    if (memoizedSerializedSize == -1) {
+      memoizedSerializedSize = schema.getSerializedSize(this);
+      setMemoizedSerializedSize(memoizedSerializedSize);
+    }
+    return memoizedSerializedSize;
+  }
+
+  private String getSerializingExceptionMessage(String target) {
+    return "Serializing "
+            + getClass().getName()
+            + " to a "
+            + target
+            + " threw an IOException (should never happen).";
+  }
+
+  protected static void checkByteStringIsUtf8(ByteString byteString)
+          throws IllegalArgumentException {
+    if (!byteString.isValidUtf8()) {
+      throw new IllegalArgumentException("Byte string is not UTF-8.");
+    }
+  }
+
+  /** Interface for an enum which signifies which field in a {@code oneof} was specified. */
+  protected interface InternalOneOfEnum {
+    /**
+     * Retrieves the field number of the field which was set in this {@code oneof}, or {@code 0} if
+     * none were.
+     */
+    int getNumber();
+  }
+
+  @Override
+  public boolean isInitialized() {
+    return MessageReflection.isInitialized(this);
+  }
+
+  /**
+   * Interface for the parent of a Builder that allows the builder to communicate invalidations back
+   * to the parent for use when using nested builders.
+   */
+  protected interface BuilderParent {
+
+    /**
+     * A builder becomes dirty whenever a field is modified -- including fields in nested builders
+     * -- and becomes clean when build() is called. Thus, when a builder becomes dirty, all its
+     * parents become dirty as well, and when it becomes clean, all its children become clean. The
+     * dirtiness state is used to invalidate certain cached values.
+     *
+     * <p>To this end, a builder calls markDirty() on its parent whenever it transitions from clean
+     * to dirty. The parent must propagate this call to its own parent, unless it was already dirty,
+     * in which case the grandparent must necessarily already be dirty as well. The parent can only
+     * transition back to "clean" after calling build() on all children.
+     */
+    void markDirty();
+  }
+
+  /** Create a nested builder. */
+  protected Message.Builder newBuilderForType(BuilderParent parent) {
+    throw new UnsupportedOperationException("Nested builder is not supported for this type.");
+  }
+
+  @Override
+  public List<String> findInitializationErrors() {
+    return MessageReflection.findMissingFields(this);
+  }
+
+  @Override
+  public String getInitializationErrorString() {
+    return MessageReflection.delimitWithCommas(findInitializationErrors());
+  }
+
+  // TODO: Clear it when all subclasses have implemented this method.
+  @Override
+  public boolean hasOneof(OneofDescriptor oneof) {
+    throw new UnsupportedOperationException("hasOneof() is not implemented.");
+  }
+
+  // TODO: Clear it when all subclasses have implemented this method.
+  @Override
+  public FieldDescriptor getOneofFieldDescriptor(OneofDescriptor oneof) {
+    throw new UnsupportedOperationException("getOneofFieldDescriptor() is not implemented.");
+  }
+
+  @Override
+  public final String toString() {
+    return TextFormatInternal.printer().printToString(this);
+  }
+
+  @Override
+  public void writeTo(final CodedOutputStream output) throws IOException {
+    MessageReflection.writeMessageTo(this, getAllFields(), output, false);
+  }
+
+  protected int memoizedSize = -1;
+
+  int getMemoizedSerializedSize() {
+    return memoizedSize;
+  }
+
+  void setMemoizedSerializedSize(int size) {
+    memoizedSize = size;
+  }
+
+  @Override
+  public int getSerializedSize() {
+    int size = memoizedSize;
+    if (size != -1) {
+      return size;
+    }
+
+    memoizedSize = MessageReflection.getSerializedSize(this, getAllFields());
+    return memoizedSize;
+  }
+
+  @Override
+  public boolean equals(final Object other) {
+    if (other == this) {
+      return true;
+    }
+    if (!(other instanceof Message)) {
+      return false;
+    }
+    final Message otherMessage = (Message) other;
+    if (getDescriptorForType() != otherMessage.getDescriptorForType()) {
+      return false;
+    }
+    return compareFields(getAllFields(), otherMessage.getAllFields())
+        && getUnknownFields().equals(otherMessage.getUnknownFields());
+  }
+
+  @Override
+  public int hashCode() {
+    int hash = memoizedHashCode;
+    if (hash == 0) {
+      hash = 41;
+      hash = (19 * hash) + getDescriptorForType().hashCode();
+      hash = hashFields(hash, getAllFields());
+      hash = (29 * hash) + getUnknownFields().hashCode();
+      memoizedHashCode = hash;
+    }
+    return hash;
+  }
+
+  private static ByteString toByteString(Object value) {
+    if (value instanceof byte[]) {
+      return ByteString.copyFrom((byte[]) value);
+    } else {
+      return (ByteString) value;
+    }
+  }
+
+  /**
+   * Compares two bytes fields. The parameters must be either a byte array or a ByteString object.
+   * They can be of different type though.
+   */
+  private static boolean compareBytes(Object a, Object b) {
+    if (a instanceof byte[] && b instanceof byte[]) {
+      return Arrays.equals((byte[]) a, (byte[]) b);
+    }
+    return toByteString(a).equals(toByteString(b));
+  }
+
+  /** Converts a list of MapEntry messages into a Map used for equals() and hashCode(). */
+  @SuppressWarnings({"rawtypes", "unchecked"})
+  private static Map convertMapEntryListToMap(List list) {
+    if (list.isEmpty()) {
+      return Collections.emptyMap();
+    }
+    Map result = new HashMap<>();
+    Iterator iterator = list.iterator();
+    Message entry = (Message) iterator.next();
+    Descriptors.Descriptor descriptor = entry.getDescriptorForType();
+    FieldDescriptor key = descriptor.findFieldByName("key");
+    FieldDescriptor value = descriptor.findFieldByName("value");
+    Object fieldValue = entry.getField(value);
+    if (fieldValue instanceof EnumValueDescriptor) {
+      fieldValue = ((EnumValueDescriptor) fieldValue).getNumber();
+    }
+    result.put(entry.getField(key), fieldValue);
+    while (iterator.hasNext()) {
+      entry = (Message) iterator.next();
+      fieldValue = entry.getField(value);
+      if (fieldValue instanceof EnumValueDescriptor) {
+        fieldValue = ((EnumValueDescriptor) fieldValue).getNumber();
+      }
+      result.put(entry.getField(key), fieldValue);
+    }
+    return result;
+  }
+
+  /** Compares two map fields. The parameters must be a list of MapEntry messages. */
+  @SuppressWarnings({"rawtypes", "unchecked"})
+  private static boolean compareMapField(Object a, Object b) {
+    Map ma = convertMapEntryListToMap((List) a);
+    Map mb = convertMapEntryListToMap((List) b);
+    return MapFieldLite.equals(ma, mb);
+  }
+
+  /**
+   * Compares two sets of fields. This method is used to implement {@link
+   * FlattenedAbstractMessage#equals(Object)} and {@link AbstractMutableMessage#equals(Object)}. It takes
+   * special care of bytes fields because immutable messages and mutable messages use different Java
+   * type to represent a bytes field and this method should be able to compare immutable messages,
+   * mutable messages and also an immutable message to a mutable message.
+   */
+  static boolean compareFields(Map<FieldDescriptor, Object> a, Map<FieldDescriptor, Object> b) {
+    if (a.size() != b.size()) {
+      return false;
+    }
+    for (FieldDescriptor descriptor : a.keySet()) {
+      if (!b.containsKey(descriptor)) {
+        return false;
+      }
+      Object value1 = a.get(descriptor);
+      Object value2 = b.get(descriptor);
+      if (descriptor.getType() == FieldDescriptor.Type.BYTES) {
+        if (descriptor.isRepeated()) {
+          List<?> list1 = (List) value1;
+          List<?> list2 = (List) value2;
+          if (list1.size() != list2.size()) {
+            return false;
+          }
+          for (int i = 0; i < list1.size(); i++) {
+            if (!compareBytes(list1.get(i), list2.get(i))) {
+              return false;
+            }
+          }
+        } else {
+          // Compares a singular bytes field.
+          if (!compareBytes(value1, value2)) {
+            return false;
+          }
+        }
+      } else if (descriptor.isMapField()) {
+        if (!compareMapField(value1, value2)) {
+          return false;
+        }
+      } else {
+        // Compare non-bytes fields.
+        if (!value1.equals(value2)) {
+          return false;
+        }
+      }
+    }
+    return true;
+  }
+
+  /** Calculates the hash code of a map field. {@code value} must be a list of MapEntry messages. */
+  @SuppressWarnings("unchecked")
+  private static int hashMapField(Object value) {
+    return MapFieldLite.calculateHashCodeForMap(convertMapEntryListToMap((List) value));
+  }
+
+  /** Get a hash code for given fields and values, using the given seed. */
+  @SuppressWarnings("unchecked")
+  protected static int hashFields(int hash, Map<FieldDescriptor, Object> map) {
+    for (Map.Entry<FieldDescriptor, Object> entry : map.entrySet()) {
+      FieldDescriptor field = entry.getKey();
+      Object value = entry.getValue();
+      hash = (37 * hash) + field.getNumber();
+      if (field.isMapField()) {
+        hash = (53 * hash) + hashMapField(value);
+      } else if (field.getType() != FieldDescriptor.Type.ENUM) {
+        hash = (53 * hash) + value.hashCode();
+      } else if (field.isRepeated()) {
+        List<? extends EnumLite> list = (List<? extends EnumLite>) value;
+        hash = (53 * hash) + Internal.hashEnumList(list);
+      } else {
+        hash = (53 * hash) + Internal.hashEnum((EnumLite) value);
+      }
+    }
+    return hash;
+  }
+
+  /**
+   * Package private helper method for AbstractParser to create UninitializedMessageException with
+   * missing field information.
+   */
+  UninitializedMessageException newUninitializedMessageException() {
+    return Builder.newUninitializedMessageException(this);
+  }
+
+  // =================================================================
+
+  /**
+   * A partial implementation of the {@link Message.Builder} interface which implements as many
+   * methods of that interface as possible in terms of other methods.
+   */
+  @SuppressWarnings("unchecked")
+  public abstract static class Builder<BuilderType extends Builder<BuilderType>> implements Message.Builder {
+
+    /**
+     * An InputStream implementations which reads from some other InputStream but is limited to a
+     * particular number of bytes. Used by mergeDelimitedFrom(). This is intentionally
+     * package-private so that UnknownFieldSet can share it.
+     */
+    static final class LimitedInputStream extends FilterInputStream {
+      private int limit;
+
+      LimitedInputStream(InputStream in, int limit) {
+        super(in);
+        this.limit = limit;
+      }
+
+      @Override
+      public int available() throws IOException {
+        return Math.min(super.available(), limit);
+      }
+
+      @Override
+      public int read() throws IOException {
+        if (limit <= 0) {
+          return -1;
+        }
+        final int result = super.read();
+        if (result >= 0) {
+          --limit;
+        }
+        return result;
+      }
+
+      @Override
+      public int read(final byte[] b, final int off, int len) throws IOException {
+        if (limit <= 0) {
+          return -1;
+        }
+        len = Math.min(len, limit);
+        final int result = super.read(b, off, len);
+        if (result >= 0) {
+          limit -= result;
+        }
+        return result;
+      }
+
+      @Override
+      public long skip(final long n) throws IOException {
+        // because we take the minimum of an int and a long, result is guaranteed to be
+        // less than or equal to Integer.MAX_INT so this cast is safe
+        int result = (int) super.skip(Math.min(n, limit));
+        if (result >= 0) {
+          // if the superclass adheres to the contract for skip, this condition is always true
+          limit -= result;
+        }
+        return result;
+      }
+    }
+
+    @Override
+    public boolean mergeDelimitedFrom(
+            final InputStream input, final ExtensionRegistryLite extensionRegistry) throws IOException {
+      final int firstByte = input.read();
+      if (firstByte == -1) {
+        return false;
+      }
+      final int size = CodedInputStream.readRawVarint32(firstByte, input);
+      final InputStream limitedInput = new LimitedInputStream(input, size);
+      mergeFrom(limitedInput, extensionRegistry);
+      return true;
+    }
+
+    @Override
+    public boolean mergeDelimitedFrom(final InputStream input) throws IOException {
+      return mergeDelimitedFrom(input, ExtensionRegistryLite.getEmptyRegistry());
+    }
+
+    @Override
+    @SuppressWarnings("unchecked") // isInstance takes care of this
+    public BuilderType mergeFrom(final MessageLite other) {
+      if (!getDefaultInstanceForType().getClass().isInstance(other)) {
+        throw new IllegalArgumentException(
+                "mergeFrom(MessageLite) can only merge messages of the same type.");
+      }
+
+      return internalMergeFrom(other);
+    }
+
+    private String getReadingExceptionMessage(String target) {
+      return "Reading "
+              + getClass().getName()
+              + " from a "
+              + target
+              + " threw an IOException (should never happen).";
+    }
+
+    // We check nulls as we iterate to avoid iterating over values twice.
+    private static <T> void addAllCheckingNulls(Iterable<T> values, List<? super T> list) {
+      if (list instanceof ArrayList && values instanceof Collection) {
+        ((ArrayList<T>) list).ensureCapacity(list.size() + ((Collection<T>) values).size());
+      }
+      int begin = list.size();
+      for (T value : values) {
+        if (value == null) {
+          // encountered a null value so we must undo our modifications prior to throwing
+          String message = "Element at index " + (list.size() - begin) + " is null.";
+          for (int i = list.size() - 1; i >= begin; i--) {
+            list.remove(i);
+          }
+          throw new NullPointerException(message);
+        }
+        list.add(value);
+      }
+    }
+
+    /** Construct an UninitializedMessageException reporting missing fields in the given message. */
+    protected static UninitializedMessageException newUninitializedMessageException(
+            MessageLite message) {
+      return new UninitializedMessageException(message);
+    }
+
+    // For binary compatibility.
+    @Deprecated
+    protected static <T> void addAll(final Iterable<T> values, final Collection<? super T> list) {
+      addAll(values, (List<T>) list);
+    }
+
+    /**
+     * Adds the {@code values} to the {@code list}. This is a helper method used by generated code.
+     * Users should ignore it.
+     *
+     * @throws NullPointerException if {@code values} or any of the elements of {@code values} is
+     *     null.
+     */
+    protected static <T> void addAll(final Iterable<T> values, final List<? super T> list) {
+      checkNotNull(values);
+      if (values instanceof LazyStringList) {
+        // For StringOrByteStringLists, check the underlying elements to avoid
+        // forcing conversions of ByteStrings to Strings.
+        // TODO: Could we just prohibit nulls in all protobuf lists and get rid of this? Is
+        // if even possible to hit this condition as all protobuf methods check for null first,
+        // right?
+        List<?> lazyValues = ((LazyStringList) values).getUnderlyingElements();
+        LazyStringList lazyList = (LazyStringList) list;
+        int begin = list.size();
+        for (Object value : lazyValues) {
+          if (value == null) {
+            // encountered a null value so we must undo our modifications prior to throwing
+            String message = "Element at index " + (lazyList.size() - begin) + " is null.";
+            for (int i = lazyList.size() - 1; i >= begin; i--) {
+              lazyList.remove(i);
+            }
+            throw new NullPointerException(message);
+          }
+          if (value instanceof ByteString) {
+            lazyList.add((ByteString) value);
+          } else {
+            lazyList.add((String) value);
+          }
+        }
+      } else {
+        if (values instanceof PrimitiveNonBoxingCollection) {
+          list.addAll((Collection<T>) values);
+        } else {
+          addAllCheckingNulls(values, list);
+        }
+      }
+    }
+
+    // The compiler produces an error if this is not declared explicitly.
+    // Method isn't abstract to bypass Java 1.6 compiler issue:
+    //     http://bugs.java.com/view_bug.do?bug_id=6908259
+    @Override
+    public BuilderType clone() {
+      throw new UnsupportedOperationException("clone() should be implemented in subclasses.");
+    }
+
+    /** TODO: Clear it when all subclasses have implemented this method. */
+    @Override
+    public boolean hasOneof(OneofDescriptor oneof) {
+      throw new UnsupportedOperationException("hasOneof() is not implemented.");
+    }
+
+    /** TODO: Clear it when all subclasses have implemented this method. */
+    @Override
+    public FieldDescriptor getOneofFieldDescriptor(OneofDescriptor oneof) {
+      throw new UnsupportedOperationException("getOneofFieldDescriptor() is not implemented.");
+    }
+
+    /** TODO: Clear it when all subclasses have implemented this method. */
+    @Override
+    public BuilderType clearOneof(OneofDescriptor oneof) {
+      throw new UnsupportedOperationException("clearOneof() is not implemented.");
+    }
+
+    @Override
+    public BuilderType clear() {
+      for (final Map.Entry<FieldDescriptor, Object> entry : getAllFields().entrySet()) {
+        clearField(entry.getKey());
+      }
+      return (BuilderType) this;
+    }
+
+    @Override
+    public List<String> findInitializationErrors() {
+      return MessageReflection.findMissingFields(this);
+    }
+
+    @Override
+    public String getInitializationErrorString() {
+      return MessageReflection.delimitWithCommas(findInitializationErrors());
+    }
+
+    protected BuilderType internalMergeFrom(MessageLite other) {
+      return mergeFrom((Message) other);
+    }
+
+    @Override
+    public BuilderType mergeFrom(final Message other) {
+      return mergeFrom(other, other.getAllFields());
+    }
+
+    BuilderType mergeFrom(final Message other, Map<FieldDescriptor, Object> allFields) {
+      if (other.getDescriptorForType() != getDescriptorForType()) {
+        throw new IllegalArgumentException(
+            "mergeFrom(Message) can only merge messages of the same type.");
+      }
+
+      // Note:  We don't attempt to verify that other's fields have valid
+      //   types.  Doing so would be a losing battle.  We'd have to verify
+      //   all sub-messages as well, and we'd have to make copies of all of
+      //   them to insure that they don't change after verification (since
+      //   the Message interface itself cannot enforce immutability of
+      //   implementations).
+
+      for (final Map.Entry<FieldDescriptor, Object> entry : allFields.entrySet()) {
+        final FieldDescriptor field = entry.getKey();
+        if (field.isRepeated()) {
+          for (final Object element : (List) entry.getValue()) {
+            addRepeatedField(field, element);
+          }
+        } else if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+          final Message existingValue = (Message) getField(field);
+          if (existingValue == existingValue.getDefaultInstanceForType()) {
+            setField(field, entry.getValue());
+          } else {
+            setField(
+                field,
+                existingValue
+                    .newBuilderForType()
+                    .mergeFrom(existingValue)
+                    .mergeFrom((Message) entry.getValue())
+                    .build());
+          }
+        } else {
+          setField(field, entry.getValue());
+        }
+      }
+
+      mergeUnknownFields(other.getUnknownFields());
+
+      return (BuilderType) this;
+    }
+
+    @Override
+    public BuilderType mergeFrom(final CodedInputStream input) throws IOException {
+      return mergeFrom(input, ExtensionRegistry.getEmptyRegistry());
+    }
+
+    @Override
+    public BuilderType mergeFrom(
+        final CodedInputStream input, final ExtensionRegistryLite extensionRegistry)
+        throws IOException {
+      boolean discardUnknown = input.shouldDiscardUnknownFields();
+      final UnknownFieldSet.Builder unknownFields =
+          discardUnknown ? null : getUnknownFieldSetBuilder();
+      MessageReflection.mergeMessageFrom(this, unknownFields, input, extensionRegistry);
+      if (unknownFields != null) {
+        setUnknownFieldSetBuilder(unknownFields);
+      }
+      return (BuilderType) this;
+    }
+
+    protected UnknownFieldSet.Builder getUnknownFieldSetBuilder() {
+      return UnknownFieldSet.newBuilder(getUnknownFields());
+    }
+
+    protected void setUnknownFieldSetBuilder(final UnknownFieldSet.Builder builder) {
+      setUnknownFields(builder.build());
+    }
+
+    @Override
+    public BuilderType mergeUnknownFields(final UnknownFieldSet unknownFields) {
+      setUnknownFields(
+          UnknownFieldSet.newBuilder(getUnknownFields()).mergeFrom(unknownFields).build());
+      return (BuilderType) this;
+    }
+
+    @Override
+    public Message.Builder getFieldBuilder(final FieldDescriptor field) {
+      throw new UnsupportedOperationException(
+          "getFieldBuilder() called on an unsupported message type.");
+    }
+
+    @Override
+    public Message.Builder getRepeatedFieldBuilder(final FieldDescriptor field, int index) {
+      throw new UnsupportedOperationException(
+          "getRepeatedFieldBuilder() called on an unsupported message type.");
+    }
+
+    @Override
+    public String toString() {
+      return TextFormatInternal.printer().printToString(this);
+    }
+
+    /** Construct an UninitializedMessageException reporting missing fields in the given message. */
+    protected static UninitializedMessageException newUninitializedMessageException(
+        Message message) {
+      return new UninitializedMessageException(MessageReflection.findMissingFields(message));
+    }
+
+    // ===============================================================
+    // The following definitions seem to be required in order to make javac
+    // not produce weird errors like:
+    //
+    // java/com/google/protobuf/DynamicMessage.java:203: types
+    //   com.google.protobuf.AbstractMessage.Builder<
+    //     com.google.protobuf.DynamicMessage.Builder> and
+    //   com.google.protobuf.AbstractMessage.Builder<
+    //     com.google.protobuf.DynamicMessage.Builder> are incompatible; both
+    //   define mergeFrom(com.google.protobuf.ByteString), but with unrelated
+    //   return types.
+    //
+    // Strangely, these lines are only needed if javac is invoked separately
+    // on AbstractMessage.java and AbstractMessageLite.java.  If javac is
+    // invoked on both simultaneously, it works.  (Or maybe the important
+    // point is whether or not DynamicMessage.java is compiled together with
+    // AbstractMessageLite.java -- not sure.)  I suspect this is a compiler
+    // bug.
+
+    public BuilderType mergeFrom(final ByteString data) throws InvalidProtocolBufferException {
+      try {
+        final CodedInputStream input = data.newCodedInput();
+        mergeFrom(input);
+        input.checkLastTagWas(0);
+        return (BuilderType) this;
+      } catch (InvalidProtocolBufferException e) {
+        throw e;
+      } catch (IOException e) {
+        throw new RuntimeException(getReadingExceptionMessage("ByteString"), e);
+      }
+    }
+
+    public BuilderType mergeFrom(
+            final ByteString data, final ExtensionRegistryLite extensionRegistry)
+            throws InvalidProtocolBufferException {
+      try {
+        final CodedInputStream input = data.newCodedInput();
+        mergeFrom(input, extensionRegistry);
+        input.checkLastTagWas(0);
+        return (BuilderType) this;
+      } catch (InvalidProtocolBufferException e) {
+        throw e;
+      } catch (IOException e) {
+        throw new RuntimeException(getReadingExceptionMessage("ByteString"), e);
+      }
+    }
+
+    public BuilderType mergeFrom(final byte[] data) throws InvalidProtocolBufferException {
+      return mergeFrom(data, 0, data.length);
+    }
+
+    public BuilderType mergeFrom(final byte[] data, final int off, final int len)
+            throws InvalidProtocolBufferException {
+      try {
+        final CodedInputStream input = CodedInputStream.newInstance(data, off, len);
+        mergeFrom(input);
+        input.checkLastTagWas(0);
+        return (BuilderType) this;
+      } catch (InvalidProtocolBufferException e) {
+        throw e;
+      } catch (IOException e) {
+        throw new RuntimeException(getReadingExceptionMessage("byte array"), e);
+      }
+    }
+
+    public BuilderType mergeFrom(final byte[] data, final ExtensionRegistryLite extensionRegistry)
+            throws InvalidProtocolBufferException {
+      return mergeFrom(data, 0, data.length, extensionRegistry);
+    }
+
+    public BuilderType mergeFrom(
+            final byte[] data,
+            final int off,
+            final int len,
+            final ExtensionRegistryLite extensionRegistry)
+            throws InvalidProtocolBufferException {
+      try {
+        final CodedInputStream input = CodedInputStream.newInstance(data, off, len);
+        mergeFrom(input, extensionRegistry);
+        input.checkLastTagWas(0);
+        return (BuilderType) this;
+      } catch (InvalidProtocolBufferException e) {
+        throw e;
+      } catch (IOException e) {
+        throw new RuntimeException(getReadingExceptionMessage("byte array"), e);
+      }
+    }
+
+    public BuilderType mergeFrom(final InputStream input) throws IOException {
+      final CodedInputStream codedInput = CodedInputStream.newInstance(input);
+      mergeFrom(codedInput);
+      codedInput.checkLastTagWas(0);
+      return (BuilderType) this;
+    }
+
+    public BuilderType mergeFrom(
+            final InputStream input, final ExtensionRegistryLite extensionRegistry) throws IOException {
+      final CodedInputStream codedInput = CodedInputStream.newInstance(input);
+      mergeFrom(codedInput, extensionRegistry);
+      codedInput.checkLastTagWas(0);
+      return (BuilderType) this;
+    }
+
+  /**
+   * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
+   * generated code.
+   */
+  @Deprecated
+  protected static int hashLong(long n) {
+    return (int) (n ^ (n >>> 32));
+  }
+
+  /**
+   * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
+   * generated code.
+   */
+  @Deprecated
+  protected static int hashBoolean(boolean b) {
+    return b ? 1231 : 1237;
+  }
+
+  /**
+   * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
+   * generated code.
+   */
+  @Deprecated
+  protected static int hashEnum(EnumLite e) {
+    return e.getNumber();
+  }
+
+  /**
+   * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
+   * generated code.
+   */
+  @Deprecated
+  protected static int hashEnumList(List<? extends EnumLite> list) {
+    int hash = 1;
+    for (EnumLite e : list) {
+      hash = 31 * hash + hashEnum(e);
+    }
+    return hash;
+  }
+}
+}
diff --git a/protobuf-api/src/main/java/com/google/protobuf/FlattenedGeneratedMessageV3.java b/protobuf-api/src/main/java/com/google/protobuf/FlattenedGeneratedMessageV3.java
new file mode 100644
index 0000000..1d0eade
--- /dev/null
+++ b/protobuf-api/src/main/java/com/google/protobuf/FlattenedGeneratedMessageV3.java
@@ -0,0 +1,4302 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+
+package com.google.protobuf;
+
+import com.google.protobuf.Descriptors.Descriptor;
+import com.google.protobuf.Descriptors.EnumDescriptor;
+import com.google.protobuf.Descriptors.EnumValueDescriptor;
+import com.google.protobuf.Descriptors.FieldDescriptor;
+import com.google.protobuf.Descriptors.FileDescriptor;
+import com.google.protobuf.Descriptors.OneofDescriptor;
+import com.google.protobuf.Internal.BooleanList;
+import com.google.protobuf.Internal.DoubleList;
+import com.google.protobuf.Internal.FloatList;
+import com.google.protobuf.Internal.IntList;
+import com.google.protobuf.Internal.LongList;
+import com.google.protobuf.Internal.ProtobufList;
+
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.ObjectStreamException;
+import java.io.OutputStream;
+import java.io.Serializable;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+import static com.google.protobuf.Internal.checkNotNull;
+
+/**
+ * All generated protocol message classes extend this class. This class implements most of the
+ * Message and Builder interfaces using Java reflection. Users can ignore this class and pretend
+ * that generated messages implement the Message interface directly.
+ *
+ * @author kenton@google.com Kenton Varda
+ */
+abstract class FlattenedGeneratedMessageV3 implements Message, Serializable {
+  private static final long serialVersionUID = 1L;
+
+  /**
+   * For testing. Allows a test to disable the optimization that avoids using field builders for
+   * nested messages until they are requested. By disabling this optimization, existing tests can be
+   * reused to test the field builders.
+   */
+  protected static boolean alwaysUseFieldBuilders = false;
+
+  /**
+   * For use by generated code only.
+   *
+   * <p>TODO: mark this private and final (breaking change)
+   */
+  protected UnknownFieldSet unknownFields;
+
+  protected FlattenedGeneratedMessageV3() {
+    unknownFields = UnknownFieldSet.getDefaultInstance();
+  }
+
+  protected FlattenedGeneratedMessageV3(Builder<?> builder) {
+    unknownFields = builder.getUnknownFields();
+  }
+
+  protected int memoizedHashCode = 0;
+
+  public ByteString toByteString() {
+    try {
+      final ByteString.CodedBuilder out = ByteString.newCodedBuilder(getSerializedSize());
+      writeTo(out.getCodedOutput());
+      return out.build();
+    } catch (IOException e) {
+      throw new RuntimeException(getSerializingExceptionMessage("ByteString"), e);
+    }
+  }
+
+  public byte[] toByteArray() {
+    try {
+      final byte[] result = new byte[getSerializedSize()];
+      final CodedOutputStream output = CodedOutputStream.newInstance(result);
+      writeTo(output);
+      output.checkNoSpaceLeft();
+      return result;
+    } catch (IOException e) {
+      throw new RuntimeException(getSerializingExceptionMessage("byte array"), e);
+    }
+  }
+
+  public void writeTo(final OutputStream output) throws IOException {
+    final int bufferSize = CodedOutputStream.computePreferredBufferSize(getSerializedSize());
+    final CodedOutputStream codedOutput = CodedOutputStream.newInstance(output, bufferSize);
+    writeTo(codedOutput);
+    codedOutput.flush();
+  }
+
+  public void writeDelimitedTo(final OutputStream output) throws IOException {
+    final int serialized = getSerializedSize();
+    final int bufferSize =
+            CodedOutputStream.computePreferredBufferSize(
+                    CodedOutputStream.computeUInt32SizeNoTag(serialized) + serialized);
+    final CodedOutputStream codedOutput = CodedOutputStream.newInstance(output, bufferSize);
+    codedOutput.writeUInt32NoTag(serialized);
+    writeTo(codedOutput);
+    codedOutput.flush();
+  }
+
+  int getSerializedSize(
+          Schema schema) {
+    int memoizedSerializedSize = getMemoizedSerializedSize();
+    if (memoizedSerializedSize == -1) {
+      memoizedSerializedSize = schema.getSerializedSize(this);
+      setMemoizedSerializedSize(memoizedSerializedSize);
+    }
+    return memoizedSerializedSize;
+  }
+
+  private String getSerializingExceptionMessage(String target) {
+    return "Serializing "
+            + getClass().getName()
+            + " to a "
+            + target
+            + " threw an IOException (should never happen).";
+  }
+
+  protected static void checkByteStringIsUtf8(ByteString byteString)
+          throws IllegalArgumentException {
+    if (!byteString.isValidUtf8()) {
+      throw new IllegalArgumentException("Byte string is not UTF-8.");
+    }
+  }
+
+  /** Interface for an enum which signifies which field in a {@code oneof} was specified. */
+  protected interface InternalOneOfEnum {
+    /**
+     * Retrieves the field number of the field which was set in this {@code oneof}, or {@code 0} if
+     * none were.
+     */
+    int getNumber();
+  }
+
+  /**
+   * Interface for the parent of a Builder that allows the builder to communicate invalidations back
+   * to the parent for use when using nested builders.
+   */
+  protected interface BuilderParent extends Message.BuilderParent{
+
+    /**
+     * A builder becomes dirty whenever a field is modified -- including fields in nested builders
+     * -- and becomes clean when build() is called. Thus, when a builder becomes dirty, all its
+     * parents become dirty as well, and when it becomes clean, all its children become clean. The
+     * dirtiness state is used to invalidate certain cached values.
+     *
+     * <p>To this end, a builder calls markDirty() on its parent whenever it transitions from clean
+     * to dirty. The parent must propagate this call to its own parent, unless it was already dirty,
+     * in which case the grandparent must necessarily already be dirty as well. The parent can only
+     * transition back to "clean" after calling build() on all children.
+     */
+    void markDirty();
+  }
+
+  public List<String> findInitializationErrors() {
+    return MessageReflection.findMissingFields(this);
+  }
+
+  public String getInitializationErrorString() {
+    return MessageReflection.delimitWithCommas(findInitializationErrors());
+  }
+
+  protected int memoizedSize = -1;
+
+  int getMemoizedSerializedSize() {
+    return memoizedSize;
+  }
+
+  void setMemoizedSerializedSize(int size) {
+    memoizedSize = size;
+  }
+
+  @Override
+  public boolean equals(final Object other) {
+    if (other == this) {
+      return true;
+    }
+    if (!(other instanceof Message)) {
+      return false;
+    }
+    final Message otherMessage = (Message) other;
+    if (getDescriptorForType() != otherMessage.getDescriptorForType()) {
+      return false;
+    }
+    return compareFields(getAllFields(), otherMessage.getAllFields())
+            && getUnknownFields().equals(otherMessage.getUnknownFields());
+  }
+
+  @Override
+  public int hashCode() {
+    int hash = memoizedHashCode;
+    if (hash == 0) {
+      hash = 41;
+      hash = (19 * hash) + getDescriptorForType().hashCode();
+      hash = hashFields(hash, getAllFields());
+      hash = (29 * hash) + getUnknownFields().hashCode();
+      memoizedHashCode = hash;
+    }
+    return hash;
+  }
+
+  private static ByteString toByteString(Object value) {
+    if (value instanceof byte[]) {
+      return ByteString.copyFrom((byte[]) value);
+    } else {
+      return (ByteString) value;
+    }
+  }
+
+  /**
+   * Compares two bytes fields. The parameters must be either a byte array or a ByteString object.
+   * They can be of different type though.
+   */
+  private static boolean compareBytes(Object a, Object b) {
+    if (a instanceof byte[] && b instanceof byte[]) {
+      return Arrays.equals((byte[]) a, (byte[]) b);
+    }
+    return toByteString(a).equals(toByteString(b));
+  }
+
+  /** Converts a list of MapEntry messages into a Map used for equals() and hashCode(). */
+  @SuppressWarnings({"rawtypes", "unchecked"})
+  private static Map convertMapEntryListToMap(List list) {
+    if (list.isEmpty()) {
+      return Collections.emptyMap();
+    }
+    Map result = new HashMap<>();
+    Iterator iterator = list.iterator();
+    Message entry = (Message) iterator.next();
+    Descriptor descriptor = entry.getDescriptorForType();
+    FieldDescriptor key = descriptor.findFieldByName("key");
+    FieldDescriptor value = descriptor.findFieldByName("value");
+    Object fieldValue = entry.getField(value);
+    if (fieldValue instanceof EnumValueDescriptor) {
+      fieldValue = ((EnumValueDescriptor) fieldValue).getNumber();
+    }
+    result.put(entry.getField(key), fieldValue);
+    while (iterator.hasNext()) {
+      entry = (Message) iterator.next();
+      fieldValue = entry.getField(value);
+      if (fieldValue instanceof EnumValueDescriptor) {
+        fieldValue = ((EnumValueDescriptor) fieldValue).getNumber();
+      }
+      result.put(entry.getField(key), fieldValue);
+    }
+    return result;
+  }
+
+  /** Compares two map fields. The parameters must be a list of MapEntry messages. */
+  @SuppressWarnings({"rawtypes", "unchecked"})
+  private static boolean compareMapField(Object a, Object b) {
+    Map ma = convertMapEntryListToMap((List) a);
+    Map mb = convertMapEntryListToMap((List) b);
+    return MapFieldLite.equals(ma, mb);
+  }
+
+  /**
+   * Compares two sets of fields. This method is used to implement {@link
+   * AbstractMessage#equals(Object)} and {@link AbstractMutableMessage#equals(Object)}. It takes
+   * special care of bytes fields because immutable messages and mutable messages use different Java
+   * type to represent a bytes field and this method should be able to compare immutable messages,
+   * mutable messages and also an immutable message to a mutable message.
+   */
+  static boolean compareFields(Map<FieldDescriptor, Object> a, Map<FieldDescriptor, Object> b) {
+    if (a.size() != b.size()) {
+      return false;
+    }
+    for (FieldDescriptor descriptor : a.keySet()) {
+      if (!b.containsKey(descriptor)) {
+        return false;
+      }
+      Object value1 = a.get(descriptor);
+      Object value2 = b.get(descriptor);
+      if (descriptor.getType() == FieldDescriptor.Type.BYTES) {
+        if (descriptor.isRepeated()) {
+          List<?> list1 = (List) value1;
+          List<?> list2 = (List) value2;
+          if (list1.size() != list2.size()) {
+            return false;
+          }
+          for (int i = 0; i < list1.size(); i++) {
+            if (!compareBytes(list1.get(i), list2.get(i))) {
+              return false;
+            }
+          }
+        } else {
+          // Compares a singular bytes field.
+          if (!compareBytes(value1, value2)) {
+            return false;
+          }
+        }
+      } else if (descriptor.isMapField()) {
+        if (!compareMapField(value1, value2)) {
+          return false;
+        }
+      } else {
+        // Compare non-bytes fields.
+        if (!value1.equals(value2)) {
+          return false;
+        }
+      }
+    }
+    return true;
+  }
+
+  /** Calculates the hash code of a map field. {@code value} must be a list of MapEntry messages. */
+  @SuppressWarnings("unchecked")
+  private static int hashMapField(Object value) {
+    return MapFieldLite.calculateHashCodeForMap(convertMapEntryListToMap((List) value));
+  }
+
+  /** Get a hash code for given fields and values, using the given seed. */
+  @SuppressWarnings("unchecked")
+  protected static int hashFields(int hash, Map<FieldDescriptor, Object> map) {
+    for (Map.Entry<FieldDescriptor, Object> entry : map.entrySet()) {
+      FieldDescriptor field = entry.getKey();
+      Object value = entry.getValue();
+      hash = (37 * hash) + field.getNumber();
+      if (field.isMapField()) {
+        hash = (53 * hash) + hashMapField(value);
+      } else if (field.getType() != FieldDescriptor.Type.ENUM) {
+        hash = (53 * hash) + value.hashCode();
+      } else if (field.isRepeated()) {
+        List<? extends Internal.EnumLite> list = (List<? extends Internal.EnumLite>) value;
+        hash = (53 * hash) + Internal.hashEnumList(list);
+      } else {
+        hash = (53 * hash) + Internal.hashEnum((Internal.EnumLite) value);
+      }
+    }
+    return hash;
+  }
+
+//  /**
+//   * Package private helper method for AbstractParser to create UninitializedMessageException with
+//   * missing field information.
+//   */
+//  UninitializedMessageException newUninitializedMessageException() {
+//    return AbstractMessage.Builder.newUninitializedMessageException(this);
+//  }
+
+  /** TODO: Remove this unnecessary intermediate implementation of this method. */
+  @Override
+  public Parser<? extends FlattenedGeneratedMessageV3> getParserForType() {
+    throw new UnsupportedOperationException("This is supposed to be overridden by subclasses.");
+  }
+
+  /**
+   * TODO: Stop using SingleFieldBuilder and remove this setting
+   *
+   * @see #setAlwaysUseFieldBuildersForTesting(boolean)
+   */
+  static void enableAlwaysUseFieldBuildersForTesting() {
+    setAlwaysUseFieldBuildersForTesting(true);
+  }
+
+  /**
+   * For testing. Allows a test to disable/re-enable the optimization that avoids using field
+   * builders for nested messages until they are requested. By disabling this optimization, existing
+   * tests can be reused to test the field builders. See {@link RepeatedFieldBuilder} and {@link
+   * SingleFieldBuilder}.
+   *
+   * <p>TODO: Stop using SingleFieldBuilder and remove this setting
+   */
+  static void setAlwaysUseFieldBuildersForTesting(boolean useBuilders) {
+    alwaysUseFieldBuilders = useBuilders;
+  }
+
+  /**
+   * Get the FieldAccessorTable for this type. We can't have the message class pass this in to the
+   * constructor because of bootstrapping trouble with DescriptorProtos.
+   */
+  protected abstract FieldAccessorTable internalGetFieldAccessorTable();
+
+  public Descriptor getDescriptorForType() {
+    return internalGetFieldAccessorTable().descriptor;
+  }
+
+  /**
+   * TODO: This method should be removed. It enables parsing directly into an
+   * "immutable" message. Have to leave it for now to support old gencode.
+   *
+   * @deprecated use newBuilder().mergeFrom() instead
+   */
+  @Deprecated
+  protected void mergeFromAndMakeImmutableInternal(
+      CodedInputStream input, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    Schema<FlattenedGeneratedMessageV3> schema = Protobuf.getInstance().schemaFor(this);
+    try {
+      schema.mergeFrom(this, CodedInputStreamReader.forCodedInput(input), extensionRegistry);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.setUnfinishedMessage(this);
+    } catch (IOException e) {
+      throw new InvalidProtocolBufferException(e).setUnfinishedMessage(this);
+    }
+    schema.makeImmutable(this);
+  }
+
+  /**
+   * Internal helper to return a modifiable map containing all the fields. The returned Map is
+   * modifiable so that the caller can add additional extension fields to implement {@link
+   * #getAllFields()}.
+   *
+   * @param getBytesForString whether to generate ByteString for string fields
+   */
+  private Map<FieldDescriptor, Object> getAllFieldsMutable(boolean getBytesForString) {
+    final TreeMap<FieldDescriptor, Object> result = new TreeMap<>();
+    final Descriptor descriptor = internalGetFieldAccessorTable().descriptor;
+    final List<FieldDescriptor> fields = descriptor.getFields();
+
+    for (int i = 0; i < fields.size(); i++) {
+      FieldDescriptor field = fields.get(i);
+      final OneofDescriptor oneofDescriptor = field.getContainingOneof();
+
+      /*
+       * If the field is part of a Oneof, then at maximum one field in the Oneof is set
+       * and it is not repeated. There is no need to iterate through the others.
+       */
+      if (oneofDescriptor != null) {
+        // Skip other fields in the Oneof we know are not set
+        i += oneofDescriptor.getFieldCount() - 1;
+        if (!hasOneof(oneofDescriptor)) {
+          // If no field is set in the Oneof, skip all the fields in the Oneof
+          continue;
+        }
+        // Get the pointer to the only field which is set in the Oneof
+        field = getOneofFieldDescriptor(oneofDescriptor);
+      } else {
+        // If we are not in a Oneof, we need to check if the field is set and if it is repeated
+        if (field.isRepeated()) {
+          final List<?> value = (List<?>) getField(field);
+          if (!value.isEmpty()) {
+            result.put(field, value);
+          }
+          continue;
+        }
+        if (!hasField(field)) {
+          continue;
+        }
+      }
+      // Add the field to the map
+      if (getBytesForString && field.getJavaType() == FieldDescriptor.JavaType.STRING) {
+        result.put(field, getFieldRaw(field));
+      } else {
+        result.put(field, getField(field));
+      }
+    }
+    return result;
+  }
+
+  // TODO: compute this at {@code build()} time in the Builder class.
+  public boolean isInitialized() {
+    for (final FieldDescriptor field : getDescriptorForType().getFields()) {
+      // Check that all required fields are present.
+      if (field.isRequired()) {
+        if (!hasField(field)) {
+          return false;
+        }
+      }
+      // Check that embedded messages are initialized.
+      if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+        if (field.isRepeated()) {
+          @SuppressWarnings("unchecked")
+          final List<Message> messageList = (List<Message>) getField(field);
+          for (final Message element : messageList) {
+            if (!element.isInitialized()) {
+              return false;
+            }
+          }
+        } else {
+          if (hasField(field) && !((Message) getField(field)).isInitialized()) {
+            return false;
+          }
+        }
+      }
+    }
+
+    return true;
+  }
+
+  public Map<FieldDescriptor, Object> getAllFields() {
+    return Collections.unmodifiableMap(getAllFieldsMutable(/* getBytesForString= */ false));
+  }
+
+  /**
+   * Returns a collection of all the fields in this message which are set and their corresponding
+   * values. A singular ("required" or "optional") field is set iff hasField() returns true for that
+   * field. A "repeated" field is set iff getRepeatedFieldCount() is greater than zero. The values
+   * are exactly what would be returned by calling {@link #getFieldRaw(FieldDescriptor)}
+   * for each field. The map is guaranteed to be a sorted map, so iterating over it will return
+   * fields in order by field number.
+   */
+  Map<FieldDescriptor, Object> getAllFieldsRaw() {
+    return Collections.unmodifiableMap(getAllFieldsMutable(/* getBytesForString= */ true));
+  }
+
+  public boolean hasOneof(final OneofDescriptor oneof) {
+    return internalGetFieldAccessorTable().getOneof(oneof).has(this);
+  }
+
+  public FieldDescriptor getOneofFieldDescriptor(final OneofDescriptor oneof) {
+    return internalGetFieldAccessorTable().getOneof(oneof).get(this);
+  }
+
+  public boolean hasField(final FieldDescriptor field) {
+    return internalGetFieldAccessorTable().getField(field).has(this);
+  }
+
+  public Object getField(final FieldDescriptor field) {
+    return internalGetFieldAccessorTable().getField(field).get(this);
+  }
+
+  /**
+   * Obtains the value of the given field, or the default value if it is not set. For primitive
+   * fields, the boxed primitive value is returned. For enum fields, the EnumValueDescriptor for the
+   * value is returned. For embedded message fields, the sub-message is returned. For repeated
+   * fields, a java.util.List is returned. For present string fields, a ByteString is returned
+   * representing the bytes that the field contains.
+   */
+  Object getFieldRaw(final FieldDescriptor field) {
+    return internalGetFieldAccessorTable().getField(field).getRaw(this);
+  }
+
+  public int getRepeatedFieldCount(final FieldDescriptor field) {
+    return internalGetFieldAccessorTable().getField(field).getRepeatedCount(this);
+  }
+
+  public Object getRepeatedField(final FieldDescriptor field, final int index) {
+    return internalGetFieldAccessorTable().getField(field).getRepeated(this, index);
+  }
+
+  // TODO: This method should be final.
+  public UnknownFieldSet getUnknownFields() {
+    return unknownFields;
+  }
+
+  // TODO: This should go away when Schema classes cannot modify immutable
+  // GeneratedMessageV3 objects anymore.
+  void setUnknownFields(UnknownFieldSet unknownFields) {
+    this.unknownFields = unknownFields;
+  }
+
+  /**
+   * Called by subclasses to parse an unknown field.
+   *
+   * <p>TODO remove this method
+   *
+   * @return {@code true} unless the tag is an end-group tag.
+   */
+  protected boolean parseUnknownField(
+      CodedInputStream input,
+      UnknownFieldSet.Builder unknownFields,
+      ExtensionRegistryLite extensionRegistry,
+      int tag)
+      throws IOException {
+    if (input.shouldDiscardUnknownFields()) {
+      return input.skipField(tag);
+    }
+    return unknownFields.mergeFieldFrom(tag, input);
+  }
+
+  /**
+   * Delegates to parseUnknownField. This method is obsolete, but we must retain it for
+   * compatibility with older generated code.
+   *
+   * <p>TODO remove this method
+   */
+  protected boolean parseUnknownFieldProto3(
+      CodedInputStream input,
+      UnknownFieldSet.Builder unknownFields,
+      ExtensionRegistryLite extensionRegistry,
+      int tag)
+      throws IOException {
+    return parseUnknownField(input, unknownFields, extensionRegistry, tag);
+  }
+
+  /** Used by generated code. */
+  @SuppressWarnings("ProtoParseWithRegistry")
+  protected static <M extends Message> M parseWithIOException(Parser<M> parser, InputStream input)
+      throws IOException {
+    try {
+      return parser.parseFrom(input);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  /** Used by generated code. */
+  protected static <M extends Message> M parseWithIOException(
+      Parser<M> parser, InputStream input, ExtensionRegistryLite extensions) throws IOException {
+    try {
+      return parser.parseFrom(input, extensions);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  /** Used by generated code. */
+  @SuppressWarnings("ProtoParseWithRegistry")
+  protected static <M extends Message> M parseWithIOException(
+      Parser<M> parser, CodedInputStream input) throws IOException {
+    try {
+      return parser.parseFrom(input);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  /** Used by generated code. */
+  protected static <M extends Message> M parseWithIOException(
+      Parser<M> parser, CodedInputStream input, ExtensionRegistryLite extensions)
+      throws IOException {
+    try {
+      return parser.parseFrom(input, extensions);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  /** Used by generated code. */
+  @SuppressWarnings("ProtoParseWithRegistry")
+  protected static <M extends Message> M parseDelimitedWithIOException(
+      Parser<M> parser, InputStream input) throws IOException {
+    try {
+      return parser.parseDelimitedFrom(input);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  /** Used by generated code. */
+  protected static <M extends Message> M parseDelimitedWithIOException(
+      Parser<M> parser, InputStream input, ExtensionRegistryLite extensions) throws IOException {
+    try {
+      return parser.parseDelimitedFrom(input, extensions);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  protected static boolean canUseUnsafe() {
+    return UnsafeUtil.hasUnsafeArrayOperations() && UnsafeUtil.hasUnsafeByteBufferOperations();
+  }
+
+  protected static IntList emptyIntList() {
+    return IntArrayList.emptyList();
+  }
+
+  // TODO: Unused. Remove.
+  protected static IntList newIntList() {
+    return new IntArrayList();
+  }
+
+  // TODO: Redundant with makeMutableCopy(). Remove.
+  protected static IntList mutableCopy(IntList list) {
+    return makeMutableCopy(list);
+  }
+
+  // TODO: Redundant with makeMutableCopy(). Remove.
+  protected static LongList mutableCopy(LongList list) {
+    return makeMutableCopy(list);
+  }
+
+  // TODO: Redundant with makeMutableCopy(). Remove.
+  protected static FloatList mutableCopy(FloatList list) {
+    return makeMutableCopy(list);
+  }
+
+  // TODO: Redundant with makeMutableCopy(). Remove.
+  protected static DoubleList mutableCopy(DoubleList list) {
+    return makeMutableCopy(list);
+  }
+
+  // TODO: Redundant with makeMutableCopy(). Remove.
+  protected static BooleanList mutableCopy(BooleanList list) {
+    return makeMutableCopy(list);
+  }
+
+  protected static LongList emptyLongList() {
+    return LongArrayList.emptyList();
+  }
+
+  // TODO: Unused. Remove.
+  protected static LongList newLongList() {
+    return new LongArrayList();
+  }
+
+  protected static FloatList emptyFloatList() {
+    return FloatArrayList.emptyList();
+  }
+
+  // TODO: Unused. Remove.
+  protected static FloatList newFloatList() {
+    return new FloatArrayList();
+  }
+
+  protected static DoubleList emptyDoubleList() {
+    return DoubleArrayList.emptyList();
+  }
+
+  // TODO: Unused. Remove.
+  protected static DoubleList newDoubleList() {
+    return new DoubleArrayList();
+  }
+
+  protected static BooleanList emptyBooleanList() {
+    return BooleanArrayList.emptyList();
+  }
+
+  // TODO: Unused. Remove.
+  protected static BooleanList newBooleanList() {
+    return new BooleanArrayList();
+  }
+
+  protected static <ListT extends ProtobufList<?>> ListT makeMutableCopy(ListT list) {
+    return makeMutableCopy(list, 0);
+  }
+
+  @SuppressWarnings("unchecked") // Guaranteed by proto runtime.
+  protected static <ListT extends ProtobufList<?>> ListT makeMutableCopy(
+      ListT list, int minCapacity) {
+    int size = list.size();
+    if (minCapacity <= size) {
+      minCapacity = size * 2;
+    }
+    if (minCapacity <= 0) {
+      minCapacity = AbstractProtobufList.DEFAULT_CAPACITY;
+    }
+
+    return (ListT) list.mutableCopyWithCapacity(minCapacity);
+  }
+
+  @SuppressWarnings("unchecked") // The empty list can be safely cast
+  protected static <T> ProtobufList<T> emptyList(Class<T> elementType) {
+    return (ProtobufList<T>) ProtobufArrayList.emptyList();
+  }
+
+  public void writeTo(final CodedOutputStream output) throws IOException {
+    MessageReflection.writeMessageTo(this, getAllFieldsRaw(), output, false);
+  }
+
+  public int getSerializedSize() {
+    int size = memoizedSize;
+    if (size != -1) {
+      return size;
+    }
+
+    memoizedSize = MessageReflection.getSerializedSize(
+        this, getAllFieldsRaw());
+    return memoizedSize;
+  }
+
+  /**
+   * This class is used to make a generated protected method inaccessible from user's code (e.g.,
+   * the {@link #newInstance} method below). When this class is used as a parameter's type in a
+   * generated protected method, the method is visible to user's code in the same package, but since
+   * the constructor of this class is private to protobuf runtime, user's code can't obtain an
+   * instance of this class and as such can't actually make a method call on the protected method.
+   */
+  protected static final class UnusedPrivateParameter {
+    static final UnusedPrivateParameter INSTANCE = new UnusedPrivateParameter();
+
+    private UnusedPrivateParameter() {}
+  }
+
+  /** Creates a new instance of this message type. Overridden in the generated code. */
+  @SuppressWarnings({"unused"})
+  protected Object newInstance(UnusedPrivateParameter unused) {
+    throw new UnsupportedOperationException("This method must be overridden by the subclass.");
+  }
+
+  /**
+   * Used by parsing constructors in generated classes.
+   *
+   * <p>TODO: remove unused method (extensions should be immutable after build)
+   */
+  protected void makeExtensionsImmutable() {
+    // Noop for messages without extensions.
+  }
+
+  /** TODO: remove this together with GeneratedMessageV3.BuilderParent. */
+  protected abstract Message.Builder newBuilderForType(BuilderParent parent);
+
+  /** TODO: generated class should implement this directly */
+  public Message.Builder newBuilderForType(final Message.BuilderParent parent) {
+    return newBuilderForType(
+        new BuilderParent() {
+          @Override
+          public void markDirty() {
+            parent.markDirty();
+          }
+        });
+  }
+
+  /** Builder class for {@link FlattenedGeneratedMessageV3}. */
+  @SuppressWarnings("unchecked")
+  public abstract static class Builder<BuilderT extends Builder<BuilderT>>
+      implements Message.Builder {
+
+    private BuilderParent builderParent;
+
+    private BuilderParentImpl meAsParent;
+
+    // Indicates that we've built a message and so we are now obligated
+    // to dispatch dirty invalidations. See GeneratedMessageV3.BuilderListener.
+    private boolean isClean;
+
+    /**
+     * This field holds either an {@link UnknownFieldSet} or {@link UnknownFieldSet.Builder}.
+     *
+     * <p>We use an object because it should only be one or the other of those things at a time and
+     * Object is the only common base. This also saves space.
+     *
+     * <p>Conversions are lazy: if {@link #setUnknownFields} is called, this will contain {@link
+     * UnknownFieldSet}. If unknown fields are merged into this builder, the current {@link
+     * UnknownFieldSet} will be converted to a {@link UnknownFieldSet.Builder} and left that way
+     * until either {@link #setUnknownFields} or {@link #buildPartial} or {@link #build} is called.
+     */
+    private Object unknownFieldsOrBuilder = UnknownFieldSet.getDefaultInstance();
+
+    protected Builder() {
+      this(null);
+    }
+
+    protected Builder(BuilderParent builderParent) {
+      this.builderParent = builderParent;
+    }
+
+    static final class LimitedInputStream extends FilterInputStream {
+      private int limit;
+
+      LimitedInputStream(InputStream in, int limit) {
+        super(in);
+        this.limit = limit;
+      }
+
+      @Override
+      public int available() throws IOException {
+        return Math.min(super.available(), limit);
+      }
+
+      @Override
+      public int read() throws IOException {
+        if (limit <= 0) {
+          return -1;
+        }
+        final int result = super.read();
+        if (result >= 0) {
+          --limit;
+        }
+        return result;
+      }
+
+      @Override
+      public int read(final byte[] b, final int off, int len) throws IOException {
+        if (limit <= 0) {
+          return -1;
+        }
+        len = Math.min(len, limit);
+        final int result = super.read(b, off, len);
+        if (result >= 0) {
+          limit -= result;
+        }
+        return result;
+      }
+
+      @Override
+      public long skip(final long n) throws IOException {
+        // because we take the minimum of an int and a long, result is guaranteed to be
+        // less than or equal to Integer.MAX_INT so this cast is safe
+        int result = (int) super.skip(Math.min(n, limit));
+        if (result >= 0) {
+          // if the superclass adheres to the contract for skip, this condition is always true
+          limit -= result;
+        }
+        return result;
+      }
+    }
+
+    @Override
+    public boolean mergeDelimitedFrom(
+            final InputStream input, final ExtensionRegistryLite extensionRegistry) throws IOException {
+      final int firstByte = input.read();
+      if (firstByte == -1) {
+        return false;
+      }
+      final int size = CodedInputStream.readRawVarint32(firstByte, input);
+      final InputStream limitedInput = new LimitedInputStream(input, size);
+      mergeFrom(limitedInput, extensionRegistry);
+      return true;
+    }
+
+    @Override
+    public boolean mergeDelimitedFrom(final InputStream input) throws IOException {
+      return mergeDelimitedFrom(input, ExtensionRegistryLite.getEmptyRegistry());
+    }
+
+    @Override
+    @SuppressWarnings("unchecked") // isInstance takes care of this
+    public BuilderT mergeFrom(final MessageLite other) {
+      if (!getDefaultInstanceForType().getClass().isInstance(other)) {
+        throw new IllegalArgumentException(
+                "mergeFrom(MessageLite) can only merge messages of the same type.");
+      }
+
+      return internalMergeFrom(other);
+    }
+
+    private String getReadingExceptionMessage(String target) {
+      return "Reading "
+              + getClass().getName()
+              + " from a "
+              + target
+              + " threw an IOException (should never happen).";
+    }
+
+    // We check nulls as we iterate to avoid iterating over values twice.
+    private static <T> void addAllCheckingNulls(Iterable<T> values, List<? super T> list) {
+      if (list instanceof ArrayList && values instanceof Collection) {
+        ((ArrayList<T>) list).ensureCapacity(list.size() + ((Collection<T>) values).size());
+      }
+      int begin = list.size();
+      for (T value : values) {
+        if (value == null) {
+          // encountered a null value so we must undo our modifications prior to throwing
+          String message = "Element at index " + (list.size() - begin) + " is null.";
+          for (int i = list.size() - 1; i >= begin; i--) {
+            list.remove(i);
+          }
+          throw new NullPointerException(message);
+        }
+        list.add(value);
+      }
+    }
+
+    /** Construct an UninitializedMessageException reporting missing fields in the given message. */
+    protected static UninitializedMessageException newUninitializedMessageException(
+            MessageLite message) {
+      return new UninitializedMessageException(message);
+    }
+
+    // For binary compatibility.
+    @Deprecated
+    protected static <T> void addAll(final Iterable<T> values, final Collection<? super T> list) {
+      addAll(values, (List<T>) list);
+    }
+
+    /**
+     * Adds the {@code values} to the {@code list}. This is a helper method used by generated code.
+     * Users should ignore it.
+     *
+     * @throws NullPointerException if {@code values} or any of the elements of {@code values} is
+     *     null.
+     */
+    protected static <T> void addAll(final Iterable<T> values, final List<? super T> list) {
+      checkNotNull(values);
+      if (values instanceof LazyStringList) {
+        // For StringOrByteStringLists, check the underlying elements to avoid
+        // forcing conversions of ByteStrings to Strings.
+        // TODO: Could we just prohibit nulls in all protobuf lists and get rid of this? Is
+        // if even possible to hit this condition as all protobuf methods check for null first,
+        // right?
+        List<?> lazyValues = ((LazyStringList) values).getUnderlyingElements();
+        LazyStringList lazyList = (LazyStringList) list;
+        int begin = list.size();
+        for (Object value : lazyValues) {
+          if (value == null) {
+            // encountered a null value so we must undo our modifications prior to throwing
+            String message = "Element at index " + (lazyList.size() - begin) + " is null.";
+            for (int i = lazyList.size() - 1; i >= begin; i--) {
+              lazyList.remove(i);
+            }
+            throw new NullPointerException(message);
+          }
+          if (value instanceof ByteString) {
+            lazyList.add((ByteString) value);
+          } else {
+            lazyList.add((String) value);
+          }
+        }
+      } else {
+        if (values instanceof PrimitiveNonBoxingCollection) {
+          list.addAll((Collection<T>) values);
+        } else {
+          addAllCheckingNulls(values, list);
+        }
+      }
+    }
+
+    @Override
+    public List<String> findInitializationErrors() {
+      return MessageReflection.findMissingFields(this);
+    }
+
+    @Override
+    public String getInitializationErrorString() {
+      return MessageReflection.delimitWithCommas(findInitializationErrors());
+    }
+
+    protected BuilderT internalMergeFrom(MessageLite other) {
+      return mergeFrom((Message) other);
+    }
+
+    @Override
+    public BuilderT mergeFrom(final Message other) {
+      return mergeFrom(other, other.getAllFields());
+    }
+
+    BuilderT mergeFrom(final Message other, Map<FieldDescriptor, Object> allFields) {
+      if (other.getDescriptorForType() != getDescriptorForType()) {
+        throw new IllegalArgumentException(
+                "mergeFrom(Message) can only merge messages of the same type.");
+      }
+
+      // Note:  We don't attempt to verify that other's fields have valid
+      //   types.  Doing so would be a losing battle.  We'd have to verify
+      //   all sub-messages as well, and we'd have to make copies of all of
+      //   them to insure that they don't change after verification (since
+      //   the Message interface itself cannot enforce immutability of
+      //   implementations).
+
+      for (final Map.Entry<FieldDescriptor, Object> entry : allFields.entrySet()) {
+        final FieldDescriptor field = entry.getKey();
+        if (field.isRepeated()) {
+          for (final Object element : (List) entry.getValue()) {
+            addRepeatedField(field, element);
+          }
+        } else if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+          final Message existingValue = (Message) getField(field);
+          if (existingValue == existingValue.getDefaultInstanceForType()) {
+            setField(field, entry.getValue());
+          } else {
+            setField(
+                    field,
+                    existingValue
+                            .newBuilderForType()
+                            .mergeFrom(existingValue)
+                            .mergeFrom((Message) entry.getValue())
+                            .build());
+          }
+        } else {
+          setField(field, entry.getValue());
+        }
+      }
+
+      mergeUnknownFields(other.getUnknownFields());
+
+      return (BuilderT) this;
+    }
+
+    @Override
+    public BuilderT mergeFrom(final CodedInputStream input) throws IOException {
+      return mergeFrom(input, ExtensionRegistry.getEmptyRegistry());
+    }
+
+    @Override
+    public BuilderT mergeFrom(
+            final CodedInputStream input, final ExtensionRegistryLite extensionRegistry)
+            throws IOException {
+      boolean discardUnknown = input.shouldDiscardUnknownFields();
+      final UnknownFieldSet.Builder unknownFields =
+              discardUnknown ? null : getUnknownFieldSetBuilder();
+      MessageReflection.mergeMessageFrom(this, unknownFields, input, extensionRegistry);
+      if (unknownFields != null) {
+        setUnknownFieldSetBuilder(unknownFields);
+      }
+      return (BuilderT) this;
+    }
+
+    @Override
+    public String toString() {
+      return TextFormatInternal.printer().printToString(this);
+    }
+
+    /** Construct an UninitializedMessageException reporting missing fields in the given message. */
+    protected static UninitializedMessageException newUninitializedMessageException(
+            Message message) {
+      return new UninitializedMessageException(MessageReflection.findMissingFields(message));
+    }
+
+    // ===============================================================
+    // The following definitions seem to be required in order to make javac
+    // not produce weird errors like:
+    //
+    // java/com/google/protobuf/DynamicMessage.java:203: types
+    //   com.google.protobuf.AbstractMessage.Builder<
+    //     com.google.protobuf.DynamicMessage.Builder> and
+    //   com.google.protobuf.AbstractMessage.Builder<
+    //     com.google.protobuf.DynamicMessage.Builder> are incompatible; both
+    //   define mergeFrom(com.google.protobuf.ByteString), but with unrelated
+    //   return types.
+    //
+    // Strangely, these lines are only needed if javac is invoked separately
+    // on AbstractMessage.java and AbstractMessageLite.java.  If javac is
+    // invoked on both simultaneously, it works.  (Or maybe the important
+    // point is whether or not DynamicMessage.java is compiled together with
+    // AbstractMessageLite.java -- not sure.)  I suspect this is a compiler
+    // bug.
+
+    public BuilderT mergeFrom(final ByteString data) throws InvalidProtocolBufferException {
+      try {
+        final CodedInputStream input = data.newCodedInput();
+        mergeFrom(input);
+        input.checkLastTagWas(0);
+        return (BuilderT) this;
+      } catch (InvalidProtocolBufferException e) {
+        throw e;
+      } catch (IOException e) {
+        throw new RuntimeException(getReadingExceptionMessage("ByteString"), e);
+      }
+    }
+
+    public BuilderT mergeFrom(
+            final ByteString data, final ExtensionRegistryLite extensionRegistry)
+            throws InvalidProtocolBufferException {
+      try {
+        final CodedInputStream input = data.newCodedInput();
+        mergeFrom(input, extensionRegistry);
+        input.checkLastTagWas(0);
+        return (BuilderT) this;
+      } catch (InvalidProtocolBufferException e) {
+        throw e;
+      } catch (IOException e) {
+        throw new RuntimeException(getReadingExceptionMessage("ByteString"), e);
+      }
+    }
+
+    public BuilderT mergeFrom(final byte[] data) throws InvalidProtocolBufferException {
+      return mergeFrom(data, 0, data.length);
+    }
+
+    public BuilderT mergeFrom(final byte[] data, final int off, final int len)
+            throws InvalidProtocolBufferException {
+      try {
+        final CodedInputStream input = CodedInputStream.newInstance(data, off, len);
+        mergeFrom(input);
+        input.checkLastTagWas(0);
+        return (BuilderT) this;
+      } catch (InvalidProtocolBufferException e) {
+        throw e;
+      } catch (IOException e) {
+        throw new RuntimeException(getReadingExceptionMessage("byte array"), e);
+      }
+    }
+
+    public BuilderT mergeFrom(final byte[] data, final ExtensionRegistryLite extensionRegistry)
+            throws InvalidProtocolBufferException {
+      return mergeFrom(data, 0, data.length, extensionRegistry);
+    }
+
+    public BuilderT mergeFrom(
+            final byte[] data,
+            final int off,
+            final int len,
+            final ExtensionRegistryLite extensionRegistry)
+            throws InvalidProtocolBufferException {
+      try {
+        final CodedInputStream input = CodedInputStream.newInstance(data, off, len);
+        mergeFrom(input, extensionRegistry);
+        input.checkLastTagWas(0);
+        return (BuilderT) this;
+      } catch (InvalidProtocolBufferException e) {
+        throw e;
+      } catch (IOException e) {
+        throw new RuntimeException(getReadingExceptionMessage("byte array"), e);
+      }
+    }
+
+    public BuilderT mergeFrom(final InputStream input) throws IOException {
+      final CodedInputStream codedInput = CodedInputStream.newInstance(input);
+      mergeFrom(codedInput);
+      codedInput.checkLastTagWas(0);
+      return (BuilderT) this;
+    }
+
+    public BuilderT mergeFrom(
+            final InputStream input, final ExtensionRegistryLite extensionRegistry) throws IOException {
+      final CodedInputStream codedInput = CodedInputStream.newInstance(input);
+      mergeFrom(codedInput, extensionRegistry);
+      codedInput.checkLastTagWas(0);
+      return (BuilderT) this;
+    }
+
+    /**
+     * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
+     * generated code.
+     */
+    @Deprecated
+    protected static int hashLong(long n) {
+      return (int) (n ^ (n >>> 32));
+    }
+
+    /**
+     * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
+     * generated code.
+     */
+    @Deprecated
+    protected static int hashBoolean(boolean b) {
+      return b ? 1231 : 1237;
+    }
+
+    /**
+     * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
+     * generated code.
+     */
+    @Deprecated
+    protected static int hashEnum(Internal.EnumLite e) {
+      return e.getNumber();
+    }
+
+    /**
+     * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
+     * generated code.
+     */
+    @Deprecated
+    protected static int hashEnumList(List<? extends Internal.EnumLite> list) {
+      int hash = 1;
+      for (Internal.EnumLite e : list) {
+        hash = 31 * hash + hashEnum(e);
+      }
+      return hash;
+    }
+
+    public void dispose() {
+      builderParent = null;
+    }
+
+    /** Called by the subclass when a message is built. */
+    protected void onBuilt() {
+      if (builderParent != null) {
+        markClean();
+      }
+    }
+
+    /**
+     * Called by the subclass or a builder to notify us that a message was built and may be cached
+     * and therefore invalidations are needed.
+     */
+    public void markClean() {
+      this.isClean = true;
+    }
+
+    /**
+     * Gets whether invalidations are needed
+     *
+     * @return whether invalidations are needed
+     */
+    protected boolean isClean() {
+      return isClean;
+    }
+
+    @Override
+    public BuilderT clone() {
+      BuilderT builder = (BuilderT) getDefaultInstanceForType().newBuilderForType();
+      builder.mergeFrom(buildPartial());
+      return builder;
+    }
+
+    /**
+     * Called by the initialization and clear code paths to allow subclasses to reset any of their
+     * builtin fields back to the initial values.
+     */
+    @Override
+    public BuilderT clear() {
+      unknownFieldsOrBuilder = UnknownFieldSet.getDefaultInstance();
+      onChanged();
+      return (BuilderT) this;
+    }
+
+    /**
+     * Get the FieldAccessorTable for this type. We can't have the message class pass this in to the
+     * constructor because of bootstrapping trouble with DescriptorProtos.
+     */
+    protected abstract FieldAccessorTable internalGetFieldAccessorTable();
+
+    @Override
+    public Descriptor getDescriptorForType() {
+      return internalGetFieldAccessorTable().descriptor;
+    }
+
+    @Override
+    public Map<FieldDescriptor, Object> getAllFields() {
+      return Collections.unmodifiableMap(getAllFieldsMutable());
+    }
+
+    /** Internal helper which returns a mutable map. */
+    private Map<FieldDescriptor, Object> getAllFieldsMutable() {
+      final TreeMap<FieldDescriptor, Object> result = new TreeMap<>();
+      final Descriptor descriptor = internalGetFieldAccessorTable().descriptor;
+      final List<FieldDescriptor> fields = descriptor.getFields();
+
+      for (int i = 0; i < fields.size(); i++) {
+        FieldDescriptor field = fields.get(i);
+        final OneofDescriptor oneofDescriptor = field.getContainingOneof();
+
+        /*
+         * If the field is part of a Oneof, then at maximum one field in the Oneof is set
+         * and it is not repeated. There is no need to iterate through the others.
+         */
+        if (oneofDescriptor != null) {
+          // Skip other fields in the Oneof we know are not set
+          i += oneofDescriptor.getFieldCount() - 1;
+          if (!hasOneof(oneofDescriptor)) {
+            // If no field is set in the Oneof, skip all the fields in the Oneof
+            continue;
+          }
+          // Get the pointer to the only field which is set in the Oneof
+          field = getOneofFieldDescriptor(oneofDescriptor);
+        } else {
+          // If we are not in a Oneof, we need to check if the field is set and if it is repeated
+          if (field.isRepeated()) {
+            final List<?> value = (List<?>) getField(field);
+            if (!value.isEmpty()) {
+              result.put(field, value);
+            }
+            continue;
+          }
+          if (!hasField(field)) {
+            continue;
+          }
+        }
+        // Add the field to the map
+        result.put(field, getField(field));
+      }
+      return result;
+    }
+
+    @Override
+    public Message.Builder newBuilderForField(final FieldDescriptor field) {
+      return internalGetFieldAccessorTable().getField(field).newBuilder();
+    }
+
+    @Override
+    public Message.Builder getFieldBuilder(final FieldDescriptor field) {
+      return internalGetFieldAccessorTable().getField(field).getBuilder(this);
+    }
+
+    @Override
+    public Message.Builder getRepeatedFieldBuilder(final FieldDescriptor field, int index) {
+      return internalGetFieldAccessorTable().getField(field).getRepeatedBuilder(this, index);
+    }
+
+    @Override
+    public boolean hasOneof(final OneofDescriptor oneof) {
+      return internalGetFieldAccessorTable().getOneof(oneof).has(this);
+    }
+
+    @Override
+    public FieldDescriptor getOneofFieldDescriptor(final OneofDescriptor oneof) {
+      return internalGetFieldAccessorTable().getOneof(oneof).get(this);
+    }
+
+    @Override
+    public boolean hasField(final FieldDescriptor field) {
+      return internalGetFieldAccessorTable().getField(field).has(this);
+    }
+
+    @Override
+    public Object getField(final FieldDescriptor field) {
+      Object object = internalGetFieldAccessorTable().getField(field).get(this);
+      if (field.isRepeated()) {
+        // The underlying list object is still modifiable at this point.
+        // Make sure not to expose the modifiable list to the caller.
+        return Collections.unmodifiableList((List<?>) object);
+      } else {
+        return object;
+      }
+    }
+
+    @Override
+    public BuilderT setField(final FieldDescriptor field, final Object value) {
+      internalGetFieldAccessorTable().getField(field).set(this, value);
+      return (BuilderT) this;
+    }
+
+    @Override
+    public BuilderT clearField(final FieldDescriptor field) {
+      internalGetFieldAccessorTable().getField(field).clear(this);
+      return (BuilderT) this;
+    }
+
+    @Override
+    public BuilderT clearOneof(final OneofDescriptor oneof) {
+      internalGetFieldAccessorTable().getOneof(oneof).clear(this);
+      return (BuilderT) this;
+    }
+
+    @Override
+    public int getRepeatedFieldCount(final FieldDescriptor field) {
+      return internalGetFieldAccessorTable().getField(field).getRepeatedCount(this);
+    }
+
+    @Override
+    public Object getRepeatedField(final FieldDescriptor field, final int index) {
+      return internalGetFieldAccessorTable().getField(field).getRepeated(this, index);
+    }
+
+    @Override
+    public BuilderT setRepeatedField(
+        final FieldDescriptor field, final int index, final Object value) {
+      internalGetFieldAccessorTable().getField(field).setRepeated(this, index, value);
+      return (BuilderT) this;
+    }
+
+    @Override
+    public BuilderT addRepeatedField(final FieldDescriptor field, final Object value) {
+      internalGetFieldAccessorTable().getField(field).addRepeated(this, value);
+      return (BuilderT) this;
+    }
+
+    private BuilderT setUnknownFieldsInternal(final UnknownFieldSet unknownFields) {
+      unknownFieldsOrBuilder = unknownFields;
+      onChanged();
+      return (BuilderT) this;
+    }
+
+    @Override
+    public BuilderT setUnknownFields(final UnknownFieldSet unknownFields) {
+      return setUnknownFieldsInternal(unknownFields);
+    }
+
+    /**
+     * This method is obsolete, but we must retain it for compatibility with older generated code.
+     */
+    protected BuilderT setUnknownFieldsProto3(final UnknownFieldSet unknownFields) {
+      return setUnknownFieldsInternal(unknownFields);
+    }
+
+    @Override
+    public BuilderT mergeUnknownFields(final UnknownFieldSet unknownFields) {
+      if (UnknownFieldSet.getDefaultInstance().equals(unknownFields)) {
+        return (BuilderT) this;
+      }
+
+      if (UnknownFieldSet.getDefaultInstance().equals(unknownFieldsOrBuilder)) {
+        unknownFieldsOrBuilder = unknownFields;
+        onChanged();
+        return (BuilderT) this;
+      }
+
+      getUnknownFieldSetBuilder().mergeFrom(unknownFields);
+      onChanged();
+      return (BuilderT) this;
+    }
+
+    @Override
+    public boolean isInitialized() {
+      for (final FieldDescriptor field : getDescriptorForType().getFields()) {
+        // Check that all required fields are present.
+        if (field.isRequired()) {
+          if (!hasField(field)) {
+            return false;
+          }
+        }
+        // Check that embedded messages are initialized.
+        if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+          if (field.isRepeated()) {
+            @SuppressWarnings("unchecked")
+            final List<Message> messageList = (List<Message>) getField(field);
+            for (final Message element : messageList) {
+              if (!element.isInitialized()) {
+                return false;
+              }
+            }
+          } else {
+            if (hasField(field) && !((Message) getField(field)).isInitialized()) {
+              return false;
+            }
+          }
+        }
+      }
+      return true;
+    }
+
+    @Override
+    public final UnknownFieldSet getUnknownFields() {
+      if (unknownFieldsOrBuilder instanceof UnknownFieldSet) {
+        return (UnknownFieldSet) unknownFieldsOrBuilder;
+      } else {
+        return ((UnknownFieldSet.Builder) unknownFieldsOrBuilder).buildPartial();
+      }
+    }
+
+    /**
+     * Called by generated subclasses to parse an unknown field.
+     *
+     * @return {@code true} unless the tag is an end-group tag.
+     */
+    protected boolean parseUnknownField(
+        CodedInputStream input, ExtensionRegistryLite extensionRegistry, int tag)
+        throws IOException {
+      if (input.shouldDiscardUnknownFields()) {
+        return input.skipField(tag);
+      }
+      return getUnknownFieldSetBuilder().mergeFieldFrom(tag, input);
+    }
+
+    /** Called by generated subclasses to add to the unknown field set. */
+    protected final void mergeUnknownLengthDelimitedField(int number, ByteString bytes) {
+      getUnknownFieldSetBuilder().mergeLengthDelimitedField(number, bytes);
+    }
+
+    /** Called by generated subclasses to add to the unknown field set. */
+    protected final void mergeUnknownVarintField(int number, int value) {
+      getUnknownFieldSetBuilder().mergeVarintField(number, value);
+    }
+
+    protected UnknownFieldSet.Builder getUnknownFieldSetBuilder() {
+      if (unknownFieldsOrBuilder instanceof UnknownFieldSet) {
+        unknownFieldsOrBuilder = ((UnknownFieldSet) unknownFieldsOrBuilder).toBuilder();
+      }
+      onChanged();
+      return (UnknownFieldSet.Builder) unknownFieldsOrBuilder;
+    }
+
+    protected void setUnknownFieldSetBuilder(UnknownFieldSet.Builder builder) {
+      unknownFieldsOrBuilder = builder;
+      onChanged();
+    }
+
+    /**
+     * Implementation of {@link BuilderParent} for giving to our children. This small inner class
+     * makes it so we don't publicly expose the BuilderParent methods.
+     */
+    private class BuilderParentImpl implements BuilderParent {
+
+      @Override
+      public void markDirty() {
+        onChanged();
+      }
+    }
+
+    /**
+     * Gets the {@link BuilderParent} for giving to our children.
+     *
+     * @return The builder parent for our children.
+     */
+    protected BuilderParent getParentForChildren() {
+      if (meAsParent == null) {
+        meAsParent = new BuilderParentImpl();
+      }
+      return meAsParent;
+    }
+
+    /**
+     * Called when a builder or one of its nested children has changed and any parent should be
+     * notified of its invalidation.
+     */
+    protected final void onChanged() {
+      if (isClean && builderParent != null) {
+        builderParent.markDirty();
+
+        // Don't keep dispatching invalidations until build is called again.
+        isClean = false;
+      }
+    }
+
+    /**
+     * Gets the map field with the given field number. This method should be overridden in the
+     * generated message class if the message contains map fields.
+     *
+     * <p>Unlike other field types, reflection support for map fields can't be implemented based on
+     * generated public API because we need to access a map field as a list in reflection API but
+     * the generated API only allows us to access it as a map. This method returns the underlying
+     * map field directly and thus enables us to access the map field as a list.
+     */
+    @SuppressWarnings({"unused", "rawtypes"})
+    protected MapFieldReflectionAccessor internalGetMapFieldReflection(int fieldNumber) {
+      return internalGetMapField(fieldNumber);
+    }
+
+    /** TODO: Remove, exists for compatibility with generated code. */
+    @Deprecated
+    @SuppressWarnings({"unused", "rawtypes"})
+    protected MapField internalGetMapField(int fieldNumber) {
+      // Note that we can't use descriptor names here because this method will
+      // be called when descriptor is being initialized.
+      throw new IllegalArgumentException("No map fields found in " + getClass().getName());
+    }
+
+    /** Like {@link #internalGetMapFieldReflection} but return a mutable version. */
+    @SuppressWarnings({"unused", "rawtypes"})
+    protected MapFieldReflectionAccessor internalGetMutableMapFieldReflection(int fieldNumber) {
+      return internalGetMutableMapField(fieldNumber);
+    }
+
+    /** TODO: Remove, exists for compatibility with generated code. */
+    @Deprecated
+    @SuppressWarnings({"unused", "rawtypes"})
+    protected MapField internalGetMutableMapField(int fieldNumber) {
+      // Note that we can't use descriptor names here because this method will
+      // be called when descriptor is being initialized.
+      throw new IllegalArgumentException("No map fields found in " + getClass().getName());
+    }
+  }
+
+  // =================================================================
+  // Extensions-related stuff
+
+  /** Extends {@link MessageOrBuilder} with extension-related functions. */
+  public interface ExtendableMessageOrBuilder<MessageT extends ExtendableMessage<MessageT>>
+      extends MessageOrBuilder {
+    // Re-define for return type covariance.
+    @Override
+    Message getDefaultInstanceForType();
+
+    /** Check if a singular extension is present. */
+    <T> boolean hasExtension(ExtensionLite<MessageT, T> extension);
+
+    /** Get the number of elements in a repeated extension. */
+    <T> int getExtensionCount(ExtensionLite<MessageT, List<T>> extension);
+
+    /** Get the value of an extension. */
+    <T> T getExtension(ExtensionLite<MessageT, T> extension);
+
+    /** Get one element of a repeated extension. */
+    <T> T getExtension(ExtensionLite<MessageT, List<T>> extension, int index);
+
+    /**
+     * Check if a singular extension is present.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    <T> boolean hasExtension(
+        Extension<MessageT, T> extension);
+    /**
+     * Check if a singular extension is present.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    <T> boolean hasExtension(
+        GeneratedExtension<MessageT, T> extension);
+    /**
+     * Get the number of elements in a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    <T> int getExtensionCount(
+        Extension<MessageT, List<T>> extension);
+    /**
+     * Get the number of elements in a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    <T> int getExtensionCount(
+        GeneratedExtension<MessageT, List<T>> extension);
+    /**
+     * Get the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    <T> T getExtension(
+        Extension<MessageT, T> extension);
+    /**
+     * Get the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    <T> T getExtension(
+        GeneratedExtension<MessageT, T> extension);
+    /**
+     * Get one element of a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    <T> T getExtension(
+        Extension<MessageT, List<T>> extension,
+        int index);
+    /**
+     * Get one element of a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    <T> T getExtension(
+        GeneratedExtension<MessageT, List<T>> extension,
+        int index);
+  }
+
+  /**
+   * Generated message classes for message types that contain extension ranges subclass this.
+   *
+   * <p>This class implements type-safe accessors for extensions. They implement all the same
+   * operations that you can do with normal fields -- e.g. "has", "get", and "getCount" -- but for
+   * extensions. The extensions are identified using instances of the class {@link
+   * GeneratedExtension}; the protocol compiler generates a static instance of this class for every
+   * extension in its input. Through the magic of generics, all is made type-safe.
+   *
+   * <p>For example, imagine you have the {@code .proto} file:
+   *
+   * <pre>
+   * option java_class = "MyProto";
+   *
+   * message Foo {
+   *   extensions 1000 to max;
+   * }
+   *
+   * extend Foo {
+   *   optional int32 bar;
+   * }
+   * </pre>
+   *
+   * <p>Then you might write code like:
+   *
+   * <pre>
+   * MyProto.Foo foo = getFoo();
+   * int i = foo.getExtension(MyProto.bar);
+   * </pre>
+   *
+   * <p>See also {@link ExtendableBuilder}.
+   */
+  public abstract static class ExtendableMessage<MessageT extends ExtendableMessage<MessageT>>
+      extends FlattenedGeneratedMessageV3 implements ExtendableMessageOrBuilder<MessageT> {
+
+    private static final long serialVersionUID = 1L;
+
+    private final FieldSet<FieldDescriptor> extensions;
+
+    protected ExtendableMessage() {
+      this.extensions = FieldSet.newFieldSet();
+    }
+
+    protected ExtendableMessage(ExtendableBuilder<MessageT, ?> builder) {
+      super(builder);
+      this.extensions = builder.buildExtensions();
+    }
+
+    private void verifyExtensionContainingType(final Extension<MessageT, ?> extension) {
+      if (extension.getDescriptor().getContainingType() != getDescriptorForType()) {
+        // This can only happen if someone uses unchecked operations.
+        throw new IllegalArgumentException(
+            "Extension is for type \""
+                + extension.getDescriptor().getContainingType().getFullName()
+                + "\" which does not match message type \""
+                + getDescriptorForType().getFullName()
+                + "\".");
+      }
+    }
+
+    /** Check if a singular extension is present. */
+    @Override
+    public final <T> boolean hasExtension(final ExtensionLite<MessageT, T> extensionLite) {
+      Extension<MessageT, T> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      return extensions.hasField(extension.getDescriptor());
+    }
+
+    /** Get the number of elements in a repeated extension. */
+    @Override
+    public final <T> int getExtensionCount(final ExtensionLite<MessageT, List<T>> extensionLite) {
+      Extension<MessageT, List<T>> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      final FieldDescriptor descriptor = extension.getDescriptor();
+      return extensions.getRepeatedFieldCount(descriptor);
+    }
+
+    /** Get the value of an extension. */
+    @Override
+    @SuppressWarnings("unchecked")
+    public final <T> T getExtension(final ExtensionLite<MessageT, T> extensionLite) {
+      Extension<MessageT, T> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      FieldDescriptor descriptor = extension.getDescriptor();
+      final Object value = extensions.getField(descriptor);
+      if (value == null) {
+        if (descriptor.isRepeated()) {
+          return (T) Collections.emptyList();
+        } else if (descriptor.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+          return (T) extension.getMessageDefaultInstance();
+        } else {
+          return (T) extension.fromReflectionType(descriptor.getDefaultValue());
+        }
+      } else {
+        return (T) extension.fromReflectionType(value);
+      }
+    }
+
+    /** Get one element of a repeated extension. */
+    @Override
+    @SuppressWarnings("unchecked")
+    public final <T> T getExtension(
+        final ExtensionLite<MessageT, List<T>> extensionLite, final int index) {
+      Extension<MessageT, List<T>> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      FieldDescriptor descriptor = extension.getDescriptor();
+      return (T)
+          extension.singularFromReflectionType(extensions.getRepeatedField(descriptor, index));
+    }
+
+    /**
+     * Check if a singular extension is present.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> boolean hasExtension(final Extension<MessageT, T> extension) {
+      return hasExtension((ExtensionLite<MessageT, T>) extension);
+    }
+    /**
+     * Check if a singular extension is present.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> boolean hasExtension(
+        final GeneratedExtension<MessageT, T> extension) {
+      return hasExtension((ExtensionLite<MessageT, T>) extension);
+    }
+    /**
+     * Get the number of elements in a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> int getExtensionCount(
+        final Extension<MessageT, List<T>> extension) {
+      return getExtensionCount((ExtensionLite<MessageT, List<T>>) extension);
+    }
+    /**
+     * Get the number of elements in a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> int getExtensionCount(
+        final GeneratedExtension<MessageT, List<T>> extension) {
+      return getExtensionCount((ExtensionLite<MessageT, List<T>>) extension);
+    }
+    /**
+     * Get the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> T getExtension(final Extension<MessageT, T> extension) {
+      return getExtension((ExtensionLite<MessageT, T>) extension);
+    }
+    /**
+     * Get the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> T getExtension(
+        final GeneratedExtension<MessageT, T> extension) {
+      return getExtension((ExtensionLite<MessageT, T>) extension);
+    }
+    /**
+     * Get one element of a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> T getExtension(
+        final Extension<MessageT, List<T>> extension, final int index) {
+      return getExtension((ExtensionLite<MessageT, List<T>>) extension, index);
+    }
+    /**
+     * Get one element of a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> T getExtension(
+        final GeneratedExtension<MessageT, List<T>> extension, final int index) {
+      return getExtension((ExtensionLite<MessageT, List<T>>) extension, index);
+    }
+
+    /** Called by subclasses to check if all extensions are initialized. */
+    protected boolean extensionsAreInitialized() {
+      return extensions.isInitialized();
+    }
+
+    // TODO: compute this in the builder at {@code build()} time.
+    @Override
+    public boolean isInitialized() {
+      return super.isInitialized() && extensionsAreInitialized();
+    }
+
+    // TODO: remove mutating method from immutable type
+    @Override
+    protected boolean parseUnknownField(
+        CodedInputStream input,
+        UnknownFieldSet.Builder unknownFields,
+        ExtensionRegistryLite extensionRegistry,
+        int tag)
+        throws IOException {
+      return MessageReflection.mergeFieldFrom(
+          input,
+          input.shouldDiscardUnknownFields() ? null : unknownFields,
+          extensionRegistry,
+          getDescriptorForType(),
+          new MessageReflection.ExtensionAdapter(extensions),
+          tag);
+    }
+
+    /**
+     * Delegates to parseUnknownField. This method is obsolete, but we must retain it for
+     * compatibility with older generated code.
+     *
+     * <p>TODO: remove mutating method from immutable type
+     */
+    @Override
+    protected boolean parseUnknownFieldProto3(
+        CodedInputStream input,
+        UnknownFieldSet.Builder unknownFields,
+        ExtensionRegistryLite extensionRegistry,
+        int tag)
+        throws IOException {
+      return parseUnknownField(input, unknownFields, extensionRegistry, tag);
+    }
+
+    /**
+     * Used by parsing constructors in generated classes.
+     *
+     * <p>TODO: remove unused method (extensions should be immutable after build)
+     */
+    @Override
+    protected void makeExtensionsImmutable() {
+      extensions.makeImmutable();
+    }
+
+    /**
+     * Used by subclasses to serialize extensions. Extension ranges may be interleaved with field
+     * numbers, but we must write them in canonical (sorted by field number) order. ExtensionWriter
+     * helps us write individual ranges of extensions at once.
+     */
+    protected class ExtensionWriter {
+      // Imagine how much simpler this code would be if Java iterators had
+      // a way to get the next element without advancing the iterator.
+
+      private final Iterator<Map.Entry<FieldDescriptor, Object>> iter = extensions.iterator();
+      private Map.Entry<FieldDescriptor, Object> next;
+      private final boolean messageSetWireFormat;
+
+      private ExtensionWriter(final boolean messageSetWireFormat) {
+        if (iter.hasNext()) {
+          next = iter.next();
+        }
+        this.messageSetWireFormat = messageSetWireFormat;
+      }
+
+      public void writeUntil(final int end, final CodedOutputStream output) throws IOException {
+        while (next != null && next.getKey().getNumber() < end) {
+          FieldDescriptor descriptor = next.getKey();
+          if (messageSetWireFormat
+              && descriptor.getLiteJavaType() == WireFormat.JavaType.MESSAGE
+              && !descriptor.isRepeated()) {
+            if (next instanceof LazyField.LazyEntry<?>) {
+              output.writeRawMessageSetExtension(
+                  descriptor.getNumber(),
+                  ((LazyField.LazyEntry<?>) next).getField().toByteString());
+            } else {
+              output.writeMessageSetExtension(descriptor.getNumber(), (Message) next.getValue());
+            }
+          } else {
+            // TODO: Taken care of following code, it may cause
+            // problem when we use LazyField for normal fields/extensions.
+            // Due to the optional field can be duplicated at the end of
+            // serialized bytes, which will make the serialized size change
+            // after lazy field parsed. So when we use LazyField globally,
+            // we need to change the following write method to write cached
+            // bytes directly rather than write the parsed message.
+            FieldSet.writeField(descriptor, next.getValue(), output);
+          }
+          if (iter.hasNext()) {
+            next = iter.next();
+          } else {
+            next = null;
+          }
+        }
+      }
+    }
+
+    protected ExtensionWriter newExtensionWriter() {
+      return new ExtensionWriter(false);
+    }
+
+    protected ExtensionWriter newMessageSetExtensionWriter() {
+      return new ExtensionWriter(true);
+    }
+
+    /** Called by subclasses to compute the size of extensions. */
+    protected int extensionsSerializedSize() {
+      return extensions.getSerializedSize();
+    }
+
+    protected int extensionsSerializedSizeAsMessageSet() {
+      return extensions.getMessageSetSerializedSize();
+    }
+
+    // ---------------------------------------------------------------
+    // Reflection
+
+    protected Map<FieldDescriptor, Object> getExtensionFields() {
+      return extensions.getAllFields();
+    }
+
+    @Override
+    public Map<FieldDescriptor, Object> getAllFields() {
+      final Map<FieldDescriptor, Object> result =
+          super.getAllFieldsMutable(/* getBytesForString= */ false);
+      result.putAll(getExtensionFields());
+      return Collections.unmodifiableMap(result);
+    }
+
+    @Override
+    public Map<FieldDescriptor, Object> getAllFieldsRaw() {
+      final Map<FieldDescriptor, Object> result =
+          super.getAllFieldsMutable(/* getBytesForString= */ false);
+      result.putAll(getExtensionFields());
+      return Collections.unmodifiableMap(result);
+    }
+
+    @Override
+    public boolean hasField(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        return extensions.hasField(field);
+      } else {
+        return super.hasField(field);
+      }
+    }
+
+    @Override
+    public Object getField(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        final Object value = extensions.getField(field);
+        if (value == null) {
+          if (field.isRepeated()) {
+            return Collections.emptyList();
+          } else if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+            // Lacking an ExtensionRegistry, we have no way to determine the
+            // extension's real type, so we return a DynamicMessage.
+            return DynamicMessage.getDefaultInstance(field.getMessageType());
+          } else {
+            return field.getDefaultValue();
+          }
+        } else {
+          return value;
+        }
+      } else {
+        return super.getField(field);
+      }
+    }
+
+    @Override
+    public int getRepeatedFieldCount(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        return extensions.getRepeatedFieldCount(field);
+      } else {
+        return super.getRepeatedFieldCount(field);
+      }
+    }
+
+    @Override
+    public Object getRepeatedField(final FieldDescriptor field, final int index) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        return extensions.getRepeatedField(field, index);
+      } else {
+        return super.getRepeatedField(field, index);
+      }
+    }
+
+    private void verifyContainingType(final FieldDescriptor field) {
+      if (field.getContainingType() != getDescriptorForType()) {
+        throw new IllegalArgumentException("FieldDescriptor does not match message type.");
+      }
+    }
+  }
+
+  /**
+   * Type used to represent generated extensions. The protocol compiler generates a static singleton
+   * instance of this class for each extension.
+   *
+   * <p>For example, imagine you have the {@code .proto} file:
+   *
+   * <pre>
+   * option java_class = "MyProto";
+   *
+   * message Foo {
+   *   extensions 1000 to max;
+   * }
+   *
+   * extend Foo {
+   *   optional int32 bar;
+   * }
+   * </pre>
+   *
+   * <p>Then, {@code MyProto.Foo.bar} has type {@code GeneratedExtension<MyProto.Foo, Integer>}.
+   *
+   * <p>In general, users should ignore the details of this type, and simply use these static
+   * singletons as parameters to the extension accessors defined in {@link GeneratedMessage.ExtendableMessage} and
+   * {@link GeneratedMessage.ExtendableBuilder}.
+   */
+  public static class GeneratedExtension<ContainingType extends Message, Type>
+          extends Extension<ContainingType, Type> {
+    // TODO:  Find ways to avoid using Java reflection within this
+    //   class.  Also try to avoid suppressing unchecked warnings.
+
+    // We can't always initialize the descriptor of a GeneratedExtension when
+    // we first construct it due to initialization order difficulties (namely,
+    // the descriptor may not have been constructed yet, since it is often
+    // constructed by the initializer of a separate module).
+    //
+    // In the case of nested extensions, we initialize the
+    // ExtensionDescriptorRetriever with an instance that uses the scoping
+    // Message's default instance to retrieve the extension's descriptor.
+    //
+    // In the case of non-nested extensions, we initialize the
+    // ExtensionDescriptorRetriever to null and rely on the outer class's static
+    // initializer to call internalInit() after the descriptor has been parsed.
+    GeneratedExtension(
+            ExtensionDescriptorRetriever descriptorRetriever,
+            Class singularType,
+            Message messageDefaultInstance,
+            ExtensionType extensionType) {
+      if (Message.class.isAssignableFrom(singularType)
+              && !singularType.isInstance(messageDefaultInstance)) {
+        throw new IllegalArgumentException(
+                "Bad messageDefaultInstance for " + singularType.getName());
+      }
+      this.descriptorRetriever = descriptorRetriever;
+      this.singularType = singularType;
+      this.messageDefaultInstance = messageDefaultInstance;
+
+      if (ProtocolMessageEnum.class.isAssignableFrom(singularType)) {
+        this.enumValueOf = getMethodOrDie(singularType, "valueOf", EnumValueDescriptor.class);
+        this.enumGetValueDescriptor = getMethodOrDie(singularType, "getValueDescriptor");
+      } else {
+        this.enumValueOf = null;
+        this.enumGetValueDescriptor = null;
+      }
+      this.extensionType = extensionType;
+    }
+
+    /** For use by generated code only. */
+    public void internalInit(final FieldDescriptor descriptor) {
+      if (descriptorRetriever != null) {
+        throw new IllegalStateException("Already initialized.");
+      }
+      descriptorRetriever =
+              new ExtensionDescriptorRetriever() {
+                @Override
+                public FieldDescriptor getDescriptor() {
+                  return descriptor;
+                }
+              };
+    }
+
+    /**
+     * Gets the descriptor for an extension. The implementation depends on whether the extension is
+     * scoped in the top level of a file or scoped in a Message.
+     */
+    static interface ExtensionDescriptorRetriever {
+      FieldDescriptor getDescriptor();
+    }
+
+    private ExtensionDescriptorRetriever descriptorRetriever;
+    private final Class singularType;
+    private final Message messageDefaultInstance;
+    private final Method enumValueOf;
+    private final Method enumGetValueDescriptor;
+    private final ExtensionType extensionType;
+
+    @Override
+    public FieldDescriptor getDescriptor() {
+      if (descriptorRetriever == null) {
+        throw new IllegalStateException("getDescriptor() called before internalInit()");
+      }
+      return descriptorRetriever.getDescriptor();
+    }
+
+    /**
+     * If the extension is an embedded message or group, returns the default instance of the
+     * message.
+     */
+    @Override
+    public Message getMessageDefaultInstance() {
+      return messageDefaultInstance;
+    }
+
+    @Override
+    protected ExtensionType getExtensionType() {
+      return extensionType;
+    }
+
+    /**
+     * Convert from the type used by the reflection accessors to the type used by native accessors.
+     * E.g., for enums, the reflection accessors use EnumValueDescriptors but the native accessors
+     * use the generated enum type.
+     */
+    @Override
+    @SuppressWarnings("unchecked")
+    protected Object fromReflectionType(final Object value) {
+      FieldDescriptor descriptor = getDescriptor();
+      if (descriptor.isRepeated()) {
+        if (descriptor.getJavaType() == FieldDescriptor.JavaType.MESSAGE
+                || descriptor.getJavaType() == FieldDescriptor.JavaType.ENUM) {
+          // Must convert the whole list.
+          final List result = new ArrayList();
+          for (final Object element : (List) value) {
+            result.add(singularFromReflectionType(element));
+          }
+          return result;
+        } else {
+          return value;
+        }
+      } else {
+        return singularFromReflectionType(value);
+      }
+    }
+
+    /**
+     * Like {@link #fromReflectionType(Object)}, but if the type is a repeated type, this converts a
+     * single element.
+     */
+    @Override
+    protected Object singularFromReflectionType(final Object value) {
+      FieldDescriptor descriptor = getDescriptor();
+      switch (descriptor.getJavaType()) {
+        case MESSAGE:
+          if (singularType.isInstance(value)) {
+            return value;
+          } else {
+            return messageDefaultInstance.newBuilderForType().mergeFrom((Message) value).build();
+          }
+        case ENUM:
+          return invokeOrDie(enumValueOf, null, (EnumValueDescriptor) value);
+        default:
+          return value;
+      }
+    }
+
+    /**
+     * Convert from the type used by the native accessors to the type used by reflection accessors.
+     * E.g., for enums, the reflection accessors use EnumValueDescriptors but the native accessors
+     * use the generated enum type.
+     */
+    @Override
+    @SuppressWarnings("unchecked")
+    protected Object toReflectionType(final Object value) {
+      FieldDescriptor descriptor = getDescriptor();
+      if (descriptor.isRepeated()) {
+        if (descriptor.getJavaType() == FieldDescriptor.JavaType.ENUM) {
+          // Must convert the whole list.
+          final List result = new ArrayList();
+          for (final Object element : (List) value) {
+            result.add(singularToReflectionType(element));
+          }
+          return result;
+        } else {
+          return value;
+        }
+      } else {
+        return singularToReflectionType(value);
+      }
+    }
+
+    /**
+     * Like {@link #toReflectionType(Object)}, but if the type is a repeated type, this converts a
+     * single element.
+     */
+    @Override
+    protected Object singularToReflectionType(final Object value) {
+      FieldDescriptor descriptor = getDescriptor();
+      switch (descriptor.getJavaType()) {
+        case ENUM:
+          return invokeOrDie(enumGetValueDescriptor, value);
+        default:
+          return value;
+      }
+    }
+
+    @Override
+    public int getNumber() {
+      return getDescriptor().getNumber();
+    }
+
+    @Override
+    public WireFormat.FieldType getLiteType() {
+      return getDescriptor().getLiteType();
+    }
+
+    @Override
+    public boolean isRepeated() {
+      return getDescriptor().isRepeated();
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public Type getDefaultValue() {
+      if (isRepeated()) {
+        return (Type) Collections.emptyList();
+      }
+      if (getDescriptor().getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+        return (Type) messageDefaultInstance;
+      }
+      return (Type) singularFromReflectionType(getDescriptor().getDefaultValue());
+    }
+  }
+
+
+  /**
+   * Generated message builders for message types that contain extension ranges subclass this.
+   *
+   * <p>This class implements type-safe accessors for extensions. They implement all the same
+   * operations that you can do with normal fields -- e.g. "get", "set", and "add" -- but for
+   * extensions. The extensions are identified using instances of the class {@link
+   * GeneratedExtension}; the protocol compiler generates a static instance of this class for every
+   * extension in its input. Through the magic of generics, all is made type-safe.
+   *
+   * <p>For example, imagine you have the {@code .proto} file:
+   *
+   * <pre>
+   * option java_class = "MyProto";
+   *
+   * message Foo {
+   *   extensions 1000 to max;
+   * }
+   *
+   * extend Foo {
+   *   optional int32 bar;
+   * }
+   * </pre>
+   *
+   * <p>Then you might write code like:
+   *
+   * <pre>
+   * MyProto.Foo foo =
+   *   MyProto.Foo.newBuilder()
+   *     .setExtension(MyProto.bar, 123)
+   *     .build();
+   * </pre>
+   *
+   * <p>See also {@link ExtendableMessage}.
+   */
+  @SuppressWarnings("unchecked")
+  public abstract static class ExtendableBuilder<
+          MessageT extends ExtendableMessage<MessageT>,
+          BuilderT extends ExtendableBuilder<MessageT, BuilderT>>
+      extends Builder<BuilderT> implements ExtendableMessageOrBuilder<MessageT> {
+
+    private FieldSet.Builder<FieldDescriptor> extensions;
+
+    protected ExtendableBuilder() {}
+
+    protected ExtendableBuilder(BuilderParent parent) {
+      super(parent);
+    }
+
+    // For immutable message conversion.
+    void internalSetExtensionSet(FieldSet<FieldDescriptor> extensions) {
+      this.extensions = FieldSet.Builder.fromFieldSet(extensions);
+    }
+
+    @Override
+    public BuilderT clear() {
+      extensions = null;
+      return super.clear();
+    }
+
+    private void ensureExtensionsIsMutable() {
+      if (extensions == null) {
+        extensions = FieldSet.newBuilder();
+      }
+    }
+
+    private void verifyExtensionContainingType(final Extension<MessageT, ?> extension) {
+      if (extension.getDescriptor().getContainingType() != getDescriptorForType()) {
+        // This can only happen if someone uses unchecked operations.
+        throw new IllegalArgumentException(
+            "Extension is for type \""
+                + extension.getDescriptor().getContainingType().getFullName()
+                + "\" which does not match message type \""
+                + getDescriptorForType().getFullName()
+                + "\".");
+      }
+    }
+
+    /** Check if a singular extension is present. */
+    @Override
+    public final <T> boolean hasExtension(final ExtensionLite<MessageT, T> extensionLite) {
+      Extension<MessageT, T> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      return extensions != null && extensions.hasField(extension.getDescriptor());
+    }
+
+    /** Get the number of elements in a repeated extension. */
+    @Override
+    public final <T> int getExtensionCount(final ExtensionLite<MessageT, List<T>> extensionLite) {
+      Extension<MessageT, List<T>> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      final FieldDescriptor descriptor = extension.getDescriptor();
+      return extensions == null ? 0 : extensions.getRepeatedFieldCount(descriptor);
+    }
+
+    /** Get the value of an extension. */
+    @Override
+    public final <T> T getExtension(final ExtensionLite<MessageT, T> extensionLite) {
+      Extension<MessageT, T> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      FieldDescriptor descriptor = extension.getDescriptor();
+      final Object value = extensions == null ? null : extensions.getField(descriptor);
+      if (value == null) {
+        if (descriptor.isRepeated()) {
+          return (T) Collections.emptyList();
+        } else if (descriptor.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+          return (T) extension.getMessageDefaultInstance();
+        } else {
+          return (T) extension.fromReflectionType(descriptor.getDefaultValue());
+        }
+      } else {
+        return (T) extension.fromReflectionType(value);
+      }
+    }
+
+    /** Get one element of a repeated extension. */
+    @Override
+    public final <T> T getExtension(
+        final ExtensionLite<MessageT, List<T>> extensionLite, final int index) {
+      Extension<MessageT, List<T>> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      FieldDescriptor descriptor = extension.getDescriptor();
+      if (extensions == null) {
+        throw new IndexOutOfBoundsException();
+      }
+      return (T)
+          extension.singularFromReflectionType(extensions.getRepeatedField(descriptor, index));
+    }
+
+    /** Set the value of an extension. */
+    public final <T> BuilderT setExtension(
+        final ExtensionLite<MessageT, T> extensionLite, final T value) {
+      Extension<MessageT, T> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      ensureExtensionsIsMutable();
+      final FieldDescriptor descriptor = extension.getDescriptor();
+      extensions.setField(descriptor, extension.toReflectionType(value));
+      onChanged();
+      return (BuilderT) this;
+    }
+
+    /** Set the value of one element of a repeated extension. */
+    public final <T> BuilderT setExtension(
+        final ExtensionLite<MessageT, List<T>> extensionLite, final int index, final T value) {
+      Extension<MessageT, List<T>> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      ensureExtensionsIsMutable();
+      final FieldDescriptor descriptor = extension.getDescriptor();
+      extensions.setRepeatedField(descriptor, index, extension.singularToReflectionType(value));
+      onChanged();
+      return (BuilderT) this;
+    }
+
+    /** Append a value to a repeated extension. */
+    public final <T> BuilderT addExtension(
+        final ExtensionLite<MessageT, List<T>> extensionLite, final T value) {
+      Extension<MessageT, List<T>> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      ensureExtensionsIsMutable();
+      final FieldDescriptor descriptor = extension.getDescriptor();
+      extensions.addRepeatedField(descriptor, extension.singularToReflectionType(value));
+      onChanged();
+      return (BuilderT) this;
+    }
+
+    /** Clear an extension. */
+    public final <T> BuilderT clearExtension(final ExtensionLite<MessageT, T> extensionLite) {
+      Extension<MessageT, T> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      ensureExtensionsIsMutable();
+      extensions.clearField(extension.getDescriptor());
+      onChanged();
+      return (BuilderT) this;
+    }
+
+    /**
+     * Check if a singular extension is present.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> boolean hasExtension(final Extension<MessageT, T> extension) {
+      return hasExtension((ExtensionLite<MessageT, T>) extension);
+    }
+    /**
+     * Check if a singular extension is present.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> boolean hasExtension(
+        final FlattenedGeneratedMessageV3.GeneratedExtension<MessageT, T> extension) {
+      return hasExtension((ExtensionLite<MessageT, T>) extension);
+    }
+    /**
+     * Get the number of elements in a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> int getExtensionCount(
+        final Extension<MessageT, List<T>> extension) {
+      return getExtensionCount((ExtensionLite<MessageT, List<T>>) extension);
+    }
+    /**
+     * Get the number of elements in a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> int getExtensionCount(
+        final FlattenedGeneratedMessageV3.GeneratedExtension<MessageT, List<T>> extension) {
+      return getExtensionCount((ExtensionLite<MessageT, List<T>>) extension);
+    }
+    /**
+     * Get the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> T getExtension(final Extension<MessageT, T> extension) {
+      return getExtension((ExtensionLite<MessageT, T>) extension);
+    }
+    /** Get the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> T getExtension(
+        final GeneratedExtension<MessageT, T> extension) {
+      return getExtension((ExtensionLite<MessageT, T>) extension);
+    }
+    /**
+     * Get the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> T getExtension(
+        final Extension<MessageT, List<T>> extension, final int index) {
+      return getExtension((ExtensionLite<MessageT, List<T>>) extension, index);
+    }
+    /**
+     * Get the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> T getExtension(
+        final GeneratedExtension<MessageT, List<T>> extension, final int index) {
+      return getExtension((ExtensionLite<MessageT, List<T>>) extension, index);
+    }
+    /**
+     * Set the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    public final <T> BuilderT setExtension(
+        final Extension<MessageT, T> extension, final T value) {
+      return setExtension((ExtensionLite<MessageT, T>) extension, value);
+    }
+    /**
+     * Set the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    public <T> BuilderT setExtension(
+        final GeneratedExtension<MessageT, T> extension, final T value) {
+      return setExtension((ExtensionLite<MessageT, T>) extension, value);
+    }
+    /**
+     * Set the value of one element of a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    public final <T> BuilderT setExtension(
+        final Extension<MessageT, List<T>> extension,
+        final int index, final T value) {
+      return setExtension((ExtensionLite<MessageT, List<T>>) extension, index, value);
+    }
+    /**
+     * Set the value of one element of a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    public <T> BuilderT setExtension(
+        final GeneratedExtension<MessageT, List<T>> extension,
+        final int index, final T value) {
+      return setExtension((ExtensionLite<MessageT, List<T>>) extension, index, value);
+    }
+    /**
+     * Append a value to a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    public final <T> BuilderT addExtension(
+        final Extension<MessageT, List<T>> extension, final T value) {
+      return addExtension((ExtensionLite<MessageT, List<T>>) extension, value);
+    }
+    /**
+     * Append a value to a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    public <T> BuilderT addExtension(
+        final GeneratedExtension<MessageT, List<T>> extension, final T value) {
+      return addExtension((ExtensionLite<MessageT, List<T>>) extension, value);
+    }
+    /**
+     * Clear an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    public final <T> BuilderT clearExtension(
+        final Extension<MessageT, T> extension) {
+      return clearExtension((ExtensionLite<MessageT, T>) extension);
+    }
+    /**
+     * Clears an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    public <T> BuilderT clearExtension(
+        final GeneratedExtension<MessageT, T> extension) {
+      return clearExtension((ExtensionLite<MessageT, T>) extension);
+    }
+
+    /** Called by subclasses to check if all extensions are initialized. */
+    protected boolean extensionsAreInitialized() {
+      return extensions == null || extensions.isInitialized();
+    }
+
+    /**
+     * Called by the build code path to create a copy of the extensions for building the message.
+     */
+    private FieldSet<FieldDescriptor> buildExtensions() {
+      return extensions == null
+          ? (FieldSet<FieldDescriptor>) FieldSet.emptySet()
+          : extensions.buildPartial();
+    }
+
+    @Override
+    public boolean isInitialized() {
+      return super.isInitialized() && extensionsAreInitialized();
+    }
+
+    // ---------------------------------------------------------------
+    // Reflection
+
+    @Override
+    public Map<FieldDescriptor, Object> getAllFields() {
+      final Map<FieldDescriptor, Object> result = super.getAllFieldsMutable();
+      if (extensions != null) {
+        result.putAll(extensions.getAllFields());
+      }
+      return Collections.unmodifiableMap(result);
+    }
+
+    @Override
+    public Object getField(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        final Object value = extensions == null ? null : extensions.getField(field);
+        if (value == null) {
+          if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+            // Lacking an ExtensionRegistry, we have no way to determine the
+            // extension's real type, so we return a DynamicMessage.
+            return DynamicMessage.getDefaultInstance(field.getMessageType());
+          } else {
+            return field.getDefaultValue();
+          }
+        } else {
+          return value;
+        }
+      } else {
+        return super.getField(field);
+      }
+    }
+
+    @Override
+    public Message.Builder getFieldBuilder(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        if (field.getJavaType() != FieldDescriptor.JavaType.MESSAGE) {
+          throw new UnsupportedOperationException(
+              "getFieldBuilder() called on a non-Message type.");
+        }
+        ensureExtensionsIsMutable();
+        final Object value = extensions.getFieldAllowBuilders(field);
+        if (value == null) {
+          Message.Builder builder = DynamicMessage.newBuilder(field.getMessageType());
+          extensions.setField(field, builder);
+          onChanged();
+          return builder;
+        } else {
+          if (value instanceof Message.Builder) {
+            return (Message.Builder) value;
+          } else if (value instanceof Message) {
+            Message.Builder builder = ((Message) value).toBuilder();
+            extensions.setField(field, builder);
+            onChanged();
+            return builder;
+          } else {
+            throw new UnsupportedOperationException(
+                "getRepeatedFieldBuilder() called on a non-Message type.");
+          }
+        }
+      } else {
+        return super.getFieldBuilder(field);
+      }
+    }
+
+    @Override
+    public int getRepeatedFieldCount(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        return extensions == null ? 0 : extensions.getRepeatedFieldCount(field);
+      } else {
+        return super.getRepeatedFieldCount(field);
+      }
+    }
+
+    @Override
+    public Object getRepeatedField(final FieldDescriptor field, final int index) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        if (extensions == null) {
+          throw new IndexOutOfBoundsException();
+        }
+        return extensions.getRepeatedField(field, index);
+      } else {
+        return super.getRepeatedField(field, index);
+      }
+    }
+
+    @Override
+    public Message.Builder getRepeatedFieldBuilder(final FieldDescriptor field, final int index) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        ensureExtensionsIsMutable();
+        if (field.getJavaType() != FieldDescriptor.JavaType.MESSAGE) {
+          throw new UnsupportedOperationException(
+              "getRepeatedFieldBuilder() called on a non-Message type.");
+        }
+        final Object value = extensions.getRepeatedFieldAllowBuilders(field, index);
+        if (value instanceof Message.Builder) {
+          return (Message.Builder) value;
+        } else if (value instanceof Message) {
+          Message.Builder builder = ((Message) value).toBuilder();
+          extensions.setRepeatedField(field, index, builder);
+          onChanged();
+          return builder;
+        } else {
+          throw new UnsupportedOperationException(
+              "getRepeatedFieldBuilder() called on a non-Message type.");
+        }
+      } else {
+        return super.getRepeatedFieldBuilder(field, index);
+      }
+    }
+
+    @Override
+    public boolean hasField(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        return extensions != null && extensions.hasField(field);
+      } else {
+        return super.hasField(field);
+      }
+    }
+
+    @Override
+    public BuilderT setField(final FieldDescriptor field, final Object value) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        ensureExtensionsIsMutable();
+        extensions.setField(field, value);
+        onChanged();
+        return (BuilderT) this;
+      } else {
+        return super.setField(field, value);
+      }
+    }
+
+    @Override
+    public BuilderT clearField(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        ensureExtensionsIsMutable();
+        extensions.clearField(field);
+        onChanged();
+        return (BuilderT) this;
+      } else {
+        return super.clearField(field);
+      }
+    }
+
+    @Override
+    public BuilderT setRepeatedField(
+        final FieldDescriptor field, final int index, final Object value) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        ensureExtensionsIsMutable();
+        extensions.setRepeatedField(field, index, value);
+        onChanged();
+        return (BuilderT) this;
+      } else {
+        return super.setRepeatedField(field, index, value);
+      }
+    }
+
+    @Override
+    public BuilderT addRepeatedField(final FieldDescriptor field, final Object value) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        ensureExtensionsIsMutable();
+        extensions.addRepeatedField(field, value);
+        onChanged();
+        return (BuilderT) this;
+      } else {
+        return super.addRepeatedField(field, value);
+      }
+    }
+
+    @Override
+    public Message.Builder newBuilderForField(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        return DynamicMessage.newBuilder(field.getMessageType());
+      } else {
+        return super.newBuilderForField(field);
+      }
+    }
+
+    protected final void mergeExtensionFields(final ExtendableMessage<?> other) {
+      if (other.extensions != null) {
+        ensureExtensionsIsMutable();
+        extensions.mergeFrom(other.extensions);
+        onChanged();
+      }
+    }
+
+    @Override
+    protected boolean parseUnknownField(
+        CodedInputStream input, ExtensionRegistryLite extensionRegistry, int tag)
+        throws IOException {
+      ensureExtensionsIsMutable();
+      return MessageReflection.mergeFieldFrom(
+          input,
+          input.shouldDiscardUnknownFields() ? null : getUnknownFieldSetBuilder(),
+          extensionRegistry,
+          getDescriptorForType(),
+          new MessageReflection.ExtensionBuilderAdapter(extensions),
+          tag);
+    }
+
+    private void verifyContainingType(final FieldDescriptor field) {
+      if (field.getContainingType() != getDescriptorForType()) {
+        throw new IllegalArgumentException("FieldDescriptor does not match message type.");
+      }
+    }
+  }
+
+  // -----------------------------------------------------------------
+
+  /**
+   * Gets the descriptor for an extension. The implementation depends on whether the extension is
+   * scoped in the top level of a file or scoped in a Message.
+   */
+  interface ExtensionDescriptorRetriever {
+    FieldDescriptor getDescriptor();
+  }
+
+  // =================================================================
+
+  /** Calls Class.getMethod and throws a RuntimeException if it fails. */
+  private static Method getMethodOrDie(
+      final Class<?> clazz, final String name, final Class<?>... params) {
+    try {
+      return clazz.getMethod(name, params);
+    } catch (NoSuchMethodException e) {
+      throw new IllegalStateException(
+          "Generated message class \"" + clazz.getName() + "\" missing method \"" + name + "\".",
+          e);
+    }
+  }
+
+  /** Calls invoke and throws a RuntimeException if it fails. */
+  @CanIgnoreReturnValue
+  private static Object invokeOrDie(
+      final Method method, final Object object, final Object... params) {
+    try {
+      return method.invoke(object, params);
+    } catch (IllegalAccessException e) {
+      throw new IllegalStateException(
+          "Couldn't use Java reflection to implement protocol message reflection.", e);
+    } catch (InvocationTargetException e) {
+      final Throwable cause = e.getCause();
+      if (cause instanceof RuntimeException) {
+        throw (RuntimeException) cause;
+      } else if (cause instanceof Error) {
+        throw (Error) cause;
+      } else {
+        throw new IllegalStateException(
+            "Unexpected exception thrown by generated accessor method.", cause);
+      }
+    }
+  }
+
+  /**
+   * Gets the map field with the given field number. This method should be overridden in the
+   * generated message class if the message contains map fields.
+   *
+   * <p>Unlike other field types, reflection support for map fields can't be implemented based on
+   * generated public API because we need to access a map field as a list in reflection API but the
+   * generated API only allows us to access it as a map. This method returns the underlying map
+   * field directly and thus enables us to access the map field as a list.
+   */
+  @SuppressWarnings("unused")
+  protected MapFieldReflectionAccessor internalGetMapFieldReflection(int fieldNumber) {
+    return internalGetMapField(fieldNumber);
+  }
+
+  /** TODO: Remove, exists for compatibility with generated code. */
+  @Deprecated
+  @SuppressWarnings({"rawtypes", "unused"})
+  protected MapField internalGetMapField(int fieldNumber) {
+    // Note that we can't use descriptor names here because this method will
+    // be called when descriptor is being initialized.
+    throw new IllegalArgumentException("No map fields found in " + getClass().getName());
+  }
+
+  /**
+   * Users should ignore this class. This class provides the implementation with access to the
+   * fields of a message object using Java reflection.
+   */
+  public static final class FieldAccessorTable {
+
+    /**
+     * Construct a FieldAccessorTable for a particular message class. Only one FieldAccessorTable
+     * should ever be constructed per class.
+     *
+     * @param descriptor The type's descriptor.
+     * @param camelCaseNames The camelcase names of all fields in the message. These are used to
+     *     derive the accessor method names.
+     * @param messageClass The message type.
+     * @param builderClass The builder type.
+     */
+    public FieldAccessorTable(
+        final Descriptor descriptor,
+        final String[] camelCaseNames,
+        final Class<? extends FlattenedGeneratedMessageV3> messageClass,
+        final Class<? extends Builder<?>> builderClass) {
+      this(descriptor, camelCaseNames);
+      ensureFieldAccessorsInitialized(messageClass, builderClass);
+    }
+
+    /**
+     * Construct a FieldAccessorTable for a particular message class without initializing
+     * FieldAccessors.
+     */
+    public FieldAccessorTable(final Descriptor descriptor, final String[] camelCaseNames) {
+      this.descriptor = descriptor;
+      this.camelCaseNames = camelCaseNames;
+      fields = new FieldAccessor[descriptor.getFields().size()];
+      oneofs = new OneofAccessor[descriptor.getOneofs().size()];
+      initialized = false;
+    }
+
+    /**
+     * Ensures the field accessors are initialized. This method is thread-safe.
+     *
+     * @param messageClass The message type.
+     * @param builderClass The builder type.
+     * @return this
+     */
+    public FieldAccessorTable ensureFieldAccessorsInitialized(
+            Class<? extends FlattenedGeneratedMessageV3> messageClass, Class<? extends Builder<?>> builderClass) {
+      if (initialized) {
+        return this;
+      }
+      synchronized (this) {
+        if (initialized) {
+          return this;
+        }
+        int fieldsSize = fields.length;
+        for (int i = 0; i < fieldsSize; i++) {
+          FieldDescriptor field = descriptor.getFields().get(i);
+          String containingOneofCamelCaseName = null;
+          if (field.getContainingOneof() != null) {
+            int index = fieldsSize + field.getContainingOneof().getIndex();
+            if (index < camelCaseNames.length) {
+              containingOneofCamelCaseName = camelCaseNames[index];
+            }
+          }
+          if (field.isRepeated()) {
+            if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+              if (field.isMapField()) {
+                fields[i] = new MapFieldAccessor(field, messageClass);
+              } else {
+                fields[i] =
+                    new RepeatedMessageFieldAccessor(
+                        field, camelCaseNames[i], messageClass, builderClass);
+              }
+            } else if (field.getJavaType() == FieldDescriptor.JavaType.ENUM) {
+              fields[i] =
+                  new RepeatedEnumFieldAccessor(
+                      field, camelCaseNames[i], messageClass, builderClass);
+            } else {
+              fields[i] =
+                  new RepeatedFieldAccessor(field, camelCaseNames[i], messageClass, builderClass);
+            }
+          } else {
+            if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+              fields[i] =
+                  new SingularMessageFieldAccessor(
+                      field,
+                      camelCaseNames[i],
+                      messageClass,
+                      builderClass,
+                      containingOneofCamelCaseName);
+            } else if (field.getJavaType() == FieldDescriptor.JavaType.ENUM) {
+              fields[i] =
+                  new SingularEnumFieldAccessor(
+                      field,
+                      camelCaseNames[i],
+                      messageClass,
+                      builderClass,
+                      containingOneofCamelCaseName);
+            } else if (field.getJavaType() == FieldDescriptor.JavaType.STRING) {
+              fields[i] =
+                  new SingularStringFieldAccessor(
+                      field,
+                      camelCaseNames[i],
+                      messageClass,
+                      builderClass,
+                      containingOneofCamelCaseName);
+            } else {
+              fields[i] =
+                  new SingularFieldAccessor(
+                      field,
+                      camelCaseNames[i],
+                      messageClass,
+                      builderClass,
+                      containingOneofCamelCaseName);
+            }
+          }
+        }
+
+        for (int i = 0; i < descriptor.getOneofs().size(); i++) {
+          if (i < descriptor.getRealOneofs().size()) {
+            oneofs[i] =
+                new RealOneofAccessor(
+                    descriptor, i, camelCaseNames[i + fieldsSize], messageClass, builderClass);
+          } else {
+            oneofs[i] = new SyntheticOneofAccessor(descriptor, i);
+          }
+        }
+
+        initialized = true;
+        camelCaseNames = null;
+        return this;
+      }
+    }
+
+    private final Descriptor descriptor;
+    private final FieldAccessor[] fields;
+    private String[] camelCaseNames;
+    private final OneofAccessor[] oneofs;
+    private volatile boolean initialized;
+
+    /** Get the FieldAccessor for a particular field. */
+    private FieldAccessor getField(final FieldDescriptor field) {
+      if (field.getContainingType() != descriptor) {
+        throw new IllegalArgumentException("FieldDescriptor does not match message type.");
+      } else if (field.isExtension()) {
+        // If this type had extensions, it would subclass ExtendableMessage,
+        // which overrides the reflection interface to handle extensions.
+        throw new IllegalArgumentException("This type does not have extensions.");
+      }
+      return fields[field.getIndex()];
+    }
+
+    /** Get the OneofAccessor for a particular oneof. */
+    private OneofAccessor getOneof(final OneofDescriptor oneof) {
+      if (oneof.getContainingType() != descriptor) {
+        throw new IllegalArgumentException("OneofDescriptor does not match message type.");
+      }
+      return oneofs[oneof.getIndex()];
+    }
+
+    /**
+     * Abstract interface that provides access to a single field. This is implemented differently
+     * depending on the field type and cardinality.
+     */
+    private interface FieldAccessor {
+      Object get(FlattenedGeneratedMessageV3 message);
+
+      Object get(FlattenedGeneratedMessageV3.Builder<?> builder);
+
+      Object getRaw(FlattenedGeneratedMessageV3 message);
+
+      void set(Builder<?> builder, Object value);
+
+      Object getRepeated(FlattenedGeneratedMessageV3 message, int index);
+
+      Object getRepeated(FlattenedGeneratedMessageV3.Builder<?> builder, int index);
+
+      void setRepeated(Builder<?> builder, int index, Object value);
+
+      void addRepeated(Builder<?> builder, Object value);
+
+      boolean has(FlattenedGeneratedMessageV3 message);
+
+      boolean has(FlattenedGeneratedMessageV3.Builder<?> builder);
+
+      int getRepeatedCount(FlattenedGeneratedMessageV3 message);
+
+      int getRepeatedCount(FlattenedGeneratedMessageV3.Builder<?> builder);
+
+      void clear(Builder<?> builder);
+
+      Message.Builder newBuilder();
+
+      Message.Builder getBuilder(FlattenedGeneratedMessageV3.Builder<?> builder);
+
+      Message.Builder getRepeatedBuilder(FlattenedGeneratedMessageV3.Builder<?> builder, int index);
+    }
+
+    /** OneofAccessor provides access to a single oneof. */
+    private static interface OneofAccessor {
+      public boolean has(final FlattenedGeneratedMessageV3 message);
+
+      public boolean has(FlattenedGeneratedMessageV3.Builder<?> builder);
+
+      public FieldDescriptor get(final FlattenedGeneratedMessageV3 message);
+
+      public FieldDescriptor get(FlattenedGeneratedMessageV3.Builder<?> builder);
+
+      public void clear(final Builder<?> builder);
+    }
+
+    /** RealOneofAccessor provides access to a single real oneof. */
+    private static class RealOneofAccessor implements OneofAccessor {
+      RealOneofAccessor(
+          final Descriptor descriptor,
+          final int oneofIndex,
+          final String camelCaseName,
+          final Class<? extends FlattenedGeneratedMessageV3> messageClass,
+          final Class<? extends Builder<?>> builderClass) {
+        this.descriptor = descriptor;
+        caseMethod = getMethodOrDie(messageClass, "get" + camelCaseName + "Case");
+        caseMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName + "Case");
+        clearMethod = getMethodOrDie(builderClass, "clear" + camelCaseName);
+      }
+
+      private final Descriptor descriptor;
+      private final Method caseMethod;
+      private final Method caseMethodBuilder;
+      private final Method clearMethod;
+
+      @Override
+      public boolean has(final FlattenedGeneratedMessageV3 message) {
+        return ((Internal.EnumLite) invokeOrDie(caseMethod, message)).getNumber() != 0;
+      }
+
+      @Override
+      public boolean has(FlattenedGeneratedMessageV3.Builder<?> builder) {
+        return ((Internal.EnumLite) invokeOrDie(caseMethodBuilder, builder)).getNumber() != 0;
+      }
+
+      @Override
+      public FieldDescriptor get(final FlattenedGeneratedMessageV3 message) {
+        int fieldNumber = ((Internal.EnumLite) invokeOrDie(caseMethod, message)).getNumber();
+        if (fieldNumber > 0) {
+          return descriptor.findFieldByNumber(fieldNumber);
+        }
+        return null;
+      }
+
+      @Override
+      public FieldDescriptor get(FlattenedGeneratedMessageV3.Builder<?> builder) {
+        int fieldNumber = ((Internal.EnumLite) invokeOrDie(caseMethodBuilder, builder)).getNumber();
+        if (fieldNumber > 0) {
+          return descriptor.findFieldByNumber(fieldNumber);
+        }
+        return null;
+      }
+
+      @Override
+      public void clear(final Builder<?> builder) {
+        // TODO: remove the unused variable
+        Object unused = invokeOrDie(clearMethod, builder);
+      }
+    }
+
+    /** SyntheticOneofAccessor provides access to a single synthetic oneof. */
+    private static class SyntheticOneofAccessor implements OneofAccessor {
+      SyntheticOneofAccessor(final Descriptor descriptor, final int oneofIndex) {
+        OneofDescriptor oneofDescriptor = descriptor.getOneofs().get(oneofIndex);
+        fieldDescriptor = oneofDescriptor.getFields().get(0);
+      }
+
+      private final FieldDescriptor fieldDescriptor;
+
+      @Override
+      public boolean has(final FlattenedGeneratedMessageV3 message) {
+        return message.hasField(fieldDescriptor);
+      }
+
+      @Override
+      public boolean has(FlattenedGeneratedMessageV3.Builder<?> builder) {
+        return builder.hasField(fieldDescriptor);
+      }
+
+      @Override
+      public FieldDescriptor get(final FlattenedGeneratedMessageV3 message) {
+        return message.hasField(fieldDescriptor) ? fieldDescriptor : null;
+      }
+
+      public FieldDescriptor get(FlattenedGeneratedMessageV3.Builder<?> builder) {
+        return builder.hasField(fieldDescriptor) ? fieldDescriptor : null;
+      }
+
+      @Override
+      public void clear(final Builder<?> builder) {
+        builder.clearField(fieldDescriptor);
+      }
+    }
+
+    // ---------------------------------------------------------------
+
+    @SuppressWarnings("SameNameButDifferent")
+    private static class SingularFieldAccessor implements FieldAccessor {
+      private interface MethodInvoker {
+        Object get(final FlattenedGeneratedMessageV3 message);
+
+        Object get(FlattenedGeneratedMessageV3.Builder<?> builder);
+
+        int getOneofFieldNumber(final FlattenedGeneratedMessageV3 message);
+
+        int getOneofFieldNumber(final FlattenedGeneratedMessageV3.Builder<?> builder);
+
+        void set(final FlattenedGeneratedMessageV3.Builder<?> builder, final Object value);
+
+        boolean has(final FlattenedGeneratedMessageV3 message);
+
+        boolean has(FlattenedGeneratedMessageV3.Builder<?> builder);
+
+        void clear(final FlattenedGeneratedMessageV3.Builder<?> builder);
+      }
+
+      private static final class ReflectionInvoker implements MethodInvoker {
+        private final Method getMethod;
+        private final Method getMethodBuilder;
+        private final Method setMethod;
+        private final Method hasMethod;
+        private final Method hasMethodBuilder;
+        private final Method clearMethod;
+        private final Method caseMethod;
+        private final Method caseMethodBuilder;
+
+        ReflectionInvoker(
+            final FieldDescriptor descriptor,
+            final String camelCaseName,
+            final Class<? extends FlattenedGeneratedMessageV3> messageClass,
+            final Class<? extends Builder<?>> builderClass,
+            final String containingOneofCamelCaseName,
+            boolean isOneofField,
+            boolean hasHasMethod) {
+          getMethod = getMethodOrDie(messageClass, "get" + camelCaseName);
+          getMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName);
+          Class<?> type = getMethod.getReturnType();
+          setMethod = getMethodOrDie(builderClass, "set" + camelCaseName, type);
+          hasMethod = hasHasMethod ? getMethodOrDie(messageClass, "has" + camelCaseName) : null;
+          hasMethodBuilder =
+              hasHasMethod ? getMethodOrDie(builderClass, "has" + camelCaseName) : null;
+          clearMethod = getMethodOrDie(builderClass, "clear" + camelCaseName);
+          caseMethod =
+              isOneofField
+                  ? getMethodOrDie(messageClass, "get" + containingOneofCamelCaseName + "Case")
+                  : null;
+          caseMethodBuilder =
+              isOneofField
+                  ? getMethodOrDie(builderClass, "get" + containingOneofCamelCaseName + "Case")
+                  : null;
+        }
+
+        @Override
+        public Object get(final FlattenedGeneratedMessageV3 message) {
+          return invokeOrDie(getMethod, message);
+        }
+
+        @Override
+        public Object get(FlattenedGeneratedMessageV3.Builder<?> builder) {
+          return invokeOrDie(getMethodBuilder, builder);
+        }
+
+        @Override
+        public int getOneofFieldNumber(final FlattenedGeneratedMessageV3 message) {
+          return ((Internal.EnumLite) invokeOrDie(caseMethod, message)).getNumber();
+        }
+
+        @Override
+        public int getOneofFieldNumber(final FlattenedGeneratedMessageV3.Builder<?> builder) {
+          return ((Internal.EnumLite) invokeOrDie(caseMethodBuilder, builder)).getNumber();
+        }
+
+        @Override
+        public void set(final FlattenedGeneratedMessageV3.Builder<?> builder, final Object value) {
+          // TODO: remove the unused variable
+          Object unused = invokeOrDie(setMethod, builder, value);
+        }
+
+        @Override
+        public boolean has(final FlattenedGeneratedMessageV3 message) {
+          return (Boolean) invokeOrDie(hasMethod, message);
+        }
+
+        @Override
+        public boolean has(FlattenedGeneratedMessageV3.Builder<?> builder) {
+          return (Boolean) invokeOrDie(hasMethodBuilder, builder);
+        }
+
+        @Override
+        public void clear(final FlattenedGeneratedMessageV3.Builder<?> builder) {
+          // TODO: remove the unused variable
+          Object unused = invokeOrDie(clearMethod, builder);
+        }
+      }
+
+      SingularFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends FlattenedGeneratedMessageV3> messageClass,
+          final Class<? extends Builder<?>> builderClass,
+          final String containingOneofCamelCaseName) {
+        isOneofField =
+            descriptor.getRealContainingOneof() != null;
+        hasHasMethod =
+            descriptor.getFile().getSyntax() == FileDescriptor.Syntax.EDITIONS && descriptor.hasPresence()
+                || descriptor.getFile().getSyntax() == FileDescriptor.Syntax.PROTO2
+                || descriptor.hasOptionalKeyword()
+                || (!isOneofField && descriptor.getJavaType() == FieldDescriptor.JavaType.MESSAGE);
+        ReflectionInvoker reflectionInvoker =
+            new ReflectionInvoker(
+                descriptor,
+                camelCaseName,
+                messageClass,
+                builderClass,
+                containingOneofCamelCaseName,
+                isOneofField,
+                hasHasMethod);
+        field = descriptor;
+        type = reflectionInvoker.getMethod.getReturnType();
+        invoker = getMethodInvoker(reflectionInvoker);
+      }
+
+      static MethodInvoker getMethodInvoker(ReflectionInvoker accessor) {
+        return accessor;
+      }
+
+      // Note:  We use Java reflection to call public methods rather than
+      //   access private fields directly as this avoids runtime security
+      //   checks.
+      protected final Class<?> type;
+      protected final FieldDescriptor field;
+      protected final boolean isOneofField;
+      protected final boolean hasHasMethod;
+      protected final MethodInvoker invoker;
+
+      @Override
+      public Object get(final FlattenedGeneratedMessageV3 message) {
+        return invoker.get(message);
+      }
+
+      @Override
+      public Object get(FlattenedGeneratedMessageV3.Builder<?> builder) {
+        return invoker.get(builder);
+      }
+
+      @Override
+      public Object getRaw(final FlattenedGeneratedMessageV3 message) {
+        return get(message);
+      }
+
+      @Override
+      public void set(final Builder<?> builder, final Object value) {
+        invoker.set(builder, value);
+      }
+
+      @Override
+      public Object getRepeated(final FlattenedGeneratedMessageV3 message, final int index) {
+        throw new UnsupportedOperationException("getRepeatedField() called on a singular field.");
+      }
+
+      @Override
+      public Object getRepeated(FlattenedGeneratedMessageV3.Builder<?> builder, int index) {
+        throw new UnsupportedOperationException("getRepeatedField() called on a singular field.");
+      }
+
+      @Override
+      public void setRepeated(final Builder<?> builder, final int index, final Object value) {
+        throw new UnsupportedOperationException("setRepeatedField() called on a singular field.");
+      }
+
+      @Override
+      public void addRepeated(final Builder<?> builder, final Object value) {
+        throw new UnsupportedOperationException("addRepeatedField() called on a singular field.");
+      }
+
+      @Override
+      public boolean has(final FlattenedGeneratedMessageV3 message) {
+        if (!hasHasMethod) {
+          if (isOneofField) {
+            return invoker.getOneofFieldNumber(message) == field.getNumber();
+          }
+          return !get(message).equals(field.getDefaultValue());
+        }
+        return invoker.has(message);
+      }
+
+      @Override
+      public boolean has(FlattenedGeneratedMessageV3.Builder<?> builder) {
+        if (!hasHasMethod) {
+          if (isOneofField) {
+            return invoker.getOneofFieldNumber(builder) == field.getNumber();
+          }
+          return !get(builder).equals(field.getDefaultValue());
+        }
+        return invoker.has(builder);
+      }
+
+      @Override
+      public int getRepeatedCount(final FlattenedGeneratedMessageV3 message) {
+        throw new UnsupportedOperationException(
+            "getRepeatedFieldSize() called on a singular field.");
+      }
+
+      @Override
+      public int getRepeatedCount(FlattenedGeneratedMessageV3.Builder<?> builder) {
+        throw new UnsupportedOperationException(
+            "getRepeatedFieldSize() called on a singular field.");
+      }
+
+      @Override
+      public void clear(final Builder<?> builder) {
+        invoker.clear(builder);
+      }
+
+      @Override
+      public Message.Builder newBuilder() {
+        throw new UnsupportedOperationException(
+            "newBuilderForField() called on a non-Message type.");
+      }
+
+      @Override
+      public Message.Builder getBuilder(FlattenedGeneratedMessageV3.Builder<?> builder) {
+        throw new UnsupportedOperationException("getFieldBuilder() called on a non-Message type.");
+      }
+
+      @Override
+      public Message.Builder getRepeatedBuilder(FlattenedGeneratedMessageV3.Builder<?> builder, int index) {
+        throw new UnsupportedOperationException(
+            "getRepeatedFieldBuilder() called on a non-Message type.");
+      }
+    }
+
+    @SuppressWarnings("SameNameButDifferent")
+    private static class RepeatedFieldAccessor implements FieldAccessor {
+      interface MethodInvoker {
+        Object get(final FlattenedGeneratedMessageV3 message);
+
+        Object get(FlattenedGeneratedMessageV3.Builder<?> builder);
+
+        Object getRepeated(final FlattenedGeneratedMessageV3 message, final int index);
+
+        Object getRepeated(FlattenedGeneratedMessageV3.Builder<?> builder, int index);
+
+        void setRepeated(
+                final FlattenedGeneratedMessageV3.Builder<?> builder, final int index, final Object value);
+
+        void addRepeated(final FlattenedGeneratedMessageV3.Builder<?> builder, final Object value);
+
+        int getRepeatedCount(final FlattenedGeneratedMessageV3 message);
+
+        int getRepeatedCount(FlattenedGeneratedMessageV3.Builder<?> builder);
+
+        void clear(final FlattenedGeneratedMessageV3.Builder<?> builder);
+      }
+
+      private static final class ReflectionInvoker implements MethodInvoker {
+        private final Method getMethod;
+        private final Method getMethodBuilder;
+        private final Method getRepeatedMethod;
+        private final Method getRepeatedMethodBuilder;
+        private final Method setRepeatedMethod;
+        private final Method addRepeatedMethod;
+        private final Method getCountMethod;
+        private final Method getCountMethodBuilder;
+        private final Method clearMethod;
+
+        ReflectionInvoker(
+            final FieldDescriptor descriptor,
+            final String camelCaseName,
+            final Class<? extends FlattenedGeneratedMessageV3> messageClass,
+            final Class<? extends Builder<?>> builderClass) {
+          getMethod = getMethodOrDie(messageClass, "get" + camelCaseName + "List");
+          getMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName + "List");
+          getRepeatedMethod = getMethodOrDie(messageClass, "get" + camelCaseName, Integer.TYPE);
+          getRepeatedMethodBuilder =
+              getMethodOrDie(builderClass, "get" + camelCaseName, Integer.TYPE);
+          Class<?> type = getRepeatedMethod.getReturnType();
+          setRepeatedMethod =
+              getMethodOrDie(builderClass, "set" + camelCaseName, Integer.TYPE, type);
+          addRepeatedMethod = getMethodOrDie(builderClass, "add" + camelCaseName, type);
+          getCountMethod = getMethodOrDie(messageClass, "get" + camelCaseName + "Count");
+          getCountMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName + "Count");
+          clearMethod = getMethodOrDie(builderClass, "clear" + camelCaseName);
+        }
+
+        @Override
+        public Object get(final FlattenedGeneratedMessageV3 message) {
+          return invokeOrDie(getMethod, message);
+        }
+
+        @Override
+        public Object get(FlattenedGeneratedMessageV3.Builder<?> builder) {
+          return invokeOrDie(getMethodBuilder, builder);
+        }
+
+        @Override
+        public Object getRepeated(final FlattenedGeneratedMessageV3 message, final int index) {
+          return invokeOrDie(getRepeatedMethod, message, index);
+        }
+
+        @Override
+        public Object getRepeated(FlattenedGeneratedMessageV3.Builder<?> builder, int index) {
+          return invokeOrDie(getRepeatedMethodBuilder, builder, index);
+        }
+
+        @Override
+        public void setRepeated(
+                final FlattenedGeneratedMessageV3.Builder<?> builder, final int index, final Object value) {
+          // TODO: remove the unused variable
+          Object unused = invokeOrDie(setRepeatedMethod, builder, index, value);
+        }
+
+        @Override
+        public void addRepeated(final FlattenedGeneratedMessageV3.Builder<?> builder, final Object value) {
+          // TODO: remove the unused variable
+          Object unused = invokeOrDie(addRepeatedMethod, builder, value);
+        }
+
+        @Override
+        public int getRepeatedCount(final FlattenedGeneratedMessageV3 message) {
+          return (Integer) invokeOrDie(getCountMethod, message);
+        }
+
+        @Override
+        public int getRepeatedCount(FlattenedGeneratedMessageV3.Builder<?> builder) {
+          return (Integer) invokeOrDie(getCountMethodBuilder, builder);
+        }
+
+        @Override
+        public void clear(final FlattenedGeneratedMessageV3.Builder<?> builder) {
+          // TODO: remove the unused variable
+          Object unused = invokeOrDie(clearMethod, builder);
+        }
+      }
+
+      protected final Class<?> type;
+      protected final MethodInvoker invoker;
+
+      RepeatedFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends FlattenedGeneratedMessageV3> messageClass,
+          final Class<? extends Builder<?>> builderClass) {
+        ReflectionInvoker reflectionInvoker =
+            new ReflectionInvoker(descriptor, camelCaseName, messageClass, builderClass);
+        type = reflectionInvoker.getRepeatedMethod.getReturnType();
+        invoker = getMethodInvoker(reflectionInvoker);
+      }
+
+      static MethodInvoker getMethodInvoker(ReflectionInvoker accessor) {
+        return accessor;
+      }
+
+      @Override
+      public Object get(final FlattenedGeneratedMessageV3 message) {
+        return invoker.get(message);
+      }
+
+      @Override
+      public Object get(FlattenedGeneratedMessageV3.Builder<?> builder) {
+        return invoker.get(builder);
+      }
+
+      @Override
+      public Object getRaw(final FlattenedGeneratedMessageV3 message) {
+        return get(message);
+      }
+
+      @Override
+      public void set(final Builder<?> builder, final Object value) {
+        // Add all the elements individually.  This serves two purposes:
+        // 1) Verifies that each element has the correct type.
+        // 2) Insures that the caller cannot modify the list later on and
+        //    have the modifications be reflected in the message.
+        clear(builder);
+        for (final Object element : (List<?>) value) {
+          addRepeated(builder, element);
+        }
+      }
+
+      @Override
+      public Object getRepeated(final FlattenedGeneratedMessageV3 message, final int index) {
+        return invoker.getRepeated(message, index);
+      }
+
+      @Override
+      public Object getRepeated(FlattenedGeneratedMessageV3.Builder<?> builder, int index) {
+        return invoker.getRepeated(builder, index);
+      }
+
+      @Override
+      public void setRepeated(final Builder<?> builder, final int index, final Object value) {
+        invoker.setRepeated(builder, index, value);
+      }
+
+      @Override
+      public void addRepeated(final Builder<?> builder, final Object value) {
+        invoker.addRepeated(builder, value);
+      }
+
+      @Override
+      public boolean has(final FlattenedGeneratedMessageV3 message) {
+        throw new UnsupportedOperationException("hasField() called on a repeated field.");
+      }
+
+      @Override
+      public boolean has(FlattenedGeneratedMessageV3.Builder<?> builder) {
+        throw new UnsupportedOperationException("hasField() called on a repeated field.");
+      }
+
+      @Override
+      public int getRepeatedCount(final FlattenedGeneratedMessageV3 message) {
+        return invoker.getRepeatedCount(message);
+      }
+
+      @Override
+      public int getRepeatedCount(FlattenedGeneratedMessageV3.Builder<?> builder) {
+        return invoker.getRepeatedCount(builder);
+      }
+
+      @Override
+      public void clear(final Builder<?> builder) {
+        invoker.clear(builder);
+      }
+
+      @Override
+      public Message.Builder newBuilder() {
+        throw new UnsupportedOperationException(
+            "newBuilderForField() called on a non-Message type.");
+      }
+
+      @Override
+      public Message.Builder getBuilder(FlattenedGeneratedMessageV3.Builder<?> builder) {
+        throw new UnsupportedOperationException("getFieldBuilder() called on a non-Message type.");
+      }
+
+      @Override
+      public Message.Builder getRepeatedBuilder(FlattenedGeneratedMessageV3.Builder<?> builder, int index) {
+        throw new UnsupportedOperationException(
+            "getRepeatedFieldBuilder() called on a non-Message type.");
+      }
+    }
+
+    private static class MapFieldAccessor implements FieldAccessor {
+      MapFieldAccessor(
+          final FieldDescriptor descriptor, final Class<? extends FlattenedGeneratedMessageV3> messageClass) {
+        field = descriptor;
+        Method getDefaultInstanceMethod = getMethodOrDie(messageClass, "getDefaultInstance");
+        MapFieldReflectionAccessor defaultMapField =
+            getMapField((FlattenedGeneratedMessageV3) invokeOrDie(getDefaultInstanceMethod, null));
+        mapEntryMessageDefaultInstance = defaultMapField.getMapEntryMessageDefaultInstance();
+      }
+
+      private final FieldDescriptor field;
+      private final Message mapEntryMessageDefaultInstance;
+
+      private MapFieldReflectionAccessor getMapField(FlattenedGeneratedMessageV3 message) {
+        return message.internalGetMapFieldReflection(field.getNumber());
+      }
+
+      private MapFieldReflectionAccessor getMapField(FlattenedGeneratedMessageV3.Builder<?> builder) {
+        return builder.internalGetMapFieldReflection(field.getNumber());
+      }
+
+      private MapFieldReflectionAccessor getMutableMapField(FlattenedGeneratedMessageV3.Builder<?> builder) {
+        return builder.internalGetMutableMapFieldReflection(field.getNumber());
+      }
+
+      private Message coerceType(Message value) {
+        if (value == null) {
+          return null;
+        }
+        if (mapEntryMessageDefaultInstance.getClass().isInstance(value)) {
+          return value;
+        }
+        // The value is not the exact right message type.  However, if it
+        // is an alternative implementation of the same type -- e.g. a
+        // DynamicMessage -- we should accept it.  In this case we can make
+        // a copy of the message.
+        return mapEntryMessageDefaultInstance.toBuilder().mergeFrom(value).build();
+      }
+
+      @Override
+      public Object get(FlattenedGeneratedMessageV3 message) {
+        List<Object> result = new ArrayList<>();
+        for (int i = 0; i < getRepeatedCount(message); i++) {
+          result.add(getRepeated(message, i));
+        }
+        return Collections.unmodifiableList(result);
+      }
+
+      @Override
+      public Object get(Builder<?> builder) {
+        List<Object> result = new ArrayList<>();
+        for (int i = 0; i < getRepeatedCount(builder); i++) {
+          result.add(getRepeated(builder, i));
+        }
+        return Collections.unmodifiableList(result);
+      }
+
+      @Override
+      public Object getRaw(FlattenedGeneratedMessageV3 message) {
+        return get(message);
+      }
+
+      @Override
+      public void set(Builder<?> builder, Object value) {
+        clear(builder);
+        for (Object entry : (List<?>) value) {
+          addRepeated(builder, entry);
+        }
+      }
+
+      @Override
+      public Object getRepeated(FlattenedGeneratedMessageV3 message, int index) {
+        return getMapField(message).getList().get(index);
+      }
+
+      @Override
+      public Object getRepeated(Builder<?> builder, int index) {
+        return getMapField(builder).getList().get(index);
+      }
+
+      @Override
+      public void setRepeated(Builder<?> builder, int index, Object value) {
+        getMutableMapField(builder).getMutableList().set(index, coerceType((Message) value));
+      }
+
+      @Override
+      public void addRepeated(Builder<?> builder, Object value) {
+        getMutableMapField(builder).getMutableList().add(coerceType((Message) value));
+      }
+
+      @Override
+      public boolean has(FlattenedGeneratedMessageV3 message) {
+        throw new UnsupportedOperationException("hasField() is not supported for repeated fields.");
+      }
+
+      @Override
+      public boolean has(Builder<?> builder) {
+        throw new UnsupportedOperationException("hasField() is not supported for repeated fields.");
+      }
+
+      @Override
+      public int getRepeatedCount(FlattenedGeneratedMessageV3 message) {
+        return getMapField(message).getList().size();
+      }
+
+      @Override
+      public int getRepeatedCount(Builder<?> builder) {
+        return getMapField(builder).getList().size();
+      }
+
+      @Override
+      public void clear(Builder<?> builder) {
+        getMutableMapField(builder).getMutableList().clear();
+      }
+
+      @Override
+      public Message.Builder newBuilder() {
+        return mapEntryMessageDefaultInstance.newBuilderForType();
+      }
+
+      @Override
+      public Message.Builder getBuilder(Builder<?> builder) {
+        throw new UnsupportedOperationException("Nested builder not supported for map fields.");
+      }
+
+      @Override
+      public Message.Builder getRepeatedBuilder(Builder<?> builder, int index) {
+        throw new UnsupportedOperationException("Map fields cannot be repeated");
+      }
+    }
+
+    // ---------------------------------------------------------------
+
+    private static final class SingularEnumFieldAccessor extends SingularFieldAccessor {
+      SingularEnumFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends FlattenedGeneratedMessageV3> messageClass,
+          final Class<? extends Builder<?>> builderClass,
+          final String containingOneofCamelCaseName) {
+        super(descriptor, camelCaseName, messageClass, builderClass, containingOneofCamelCaseName);
+
+        enumDescriptor = descriptor.getEnumType();
+
+        valueOfMethod = getMethodOrDie(type, "valueOf", EnumValueDescriptor.class);
+        getValueDescriptorMethod = getMethodOrDie(type, "getValueDescriptor");
+
+        supportUnknownEnumValue = !descriptor.legacyEnumFieldTreatedAsClosed();
+        if (supportUnknownEnumValue) {
+          getValueMethod = getMethodOrDie(messageClass, "get" + camelCaseName + "Value");
+          getValueMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName + "Value");
+          setValueMethod = getMethodOrDie(builderClass, "set" + camelCaseName + "Value", int.class);
+        }
+      }
+
+      private final EnumDescriptor enumDescriptor;
+
+      private final Method valueOfMethod;
+      private final Method getValueDescriptorMethod;
+
+      private final boolean supportUnknownEnumValue;
+      private Method getValueMethod;
+      private Method getValueMethodBuilder;
+      private Method setValueMethod;
+
+      @Override
+      public Object get(final FlattenedGeneratedMessageV3 message) {
+        if (supportUnknownEnumValue) {
+          int value = (Integer) invokeOrDie(getValueMethod, message);
+          return enumDescriptor.findValueByNumberCreatingIfUnknown(value);
+        }
+        return invokeOrDie(getValueDescriptorMethod, super.get(message));
+      }
+
+      @Override
+      public Object get(final FlattenedGeneratedMessageV3.Builder<?> builder) {
+        if (supportUnknownEnumValue) {
+          int value = (Integer) invokeOrDie(getValueMethodBuilder, builder);
+          return enumDescriptor.findValueByNumberCreatingIfUnknown(value);
+        }
+        return invokeOrDie(getValueDescriptorMethod, super.get(builder));
+      }
+
+      @Override
+      public void set(final Builder<?> builder, final Object value) {
+        if (supportUnknownEnumValue) {
+          // TODO: remove the unused variable
+          Object unused =
+              invokeOrDie(setValueMethod, builder, ((EnumValueDescriptor) value).getNumber());
+          return;
+        }
+        super.set(builder, invokeOrDie(valueOfMethod, null, value));
+      }
+    }
+
+    private static final class RepeatedEnumFieldAccessor extends RepeatedFieldAccessor {
+      RepeatedEnumFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends FlattenedGeneratedMessageV3> messageClass,
+          final Class<? extends Builder<?>> builderClass) {
+        super(descriptor, camelCaseName, messageClass, builderClass);
+
+        enumDescriptor = descriptor.getEnumType();
+
+        valueOfMethod = getMethodOrDie(type, "valueOf", EnumValueDescriptor.class);
+        getValueDescriptorMethod = getMethodOrDie(type, "getValueDescriptor");
+
+        supportUnknownEnumValue = !descriptor.legacyEnumFieldTreatedAsClosed();
+        if (supportUnknownEnumValue) {
+          getRepeatedValueMethod =
+              getMethodOrDie(messageClass, "get" + camelCaseName + "Value", int.class);
+          getRepeatedValueMethodBuilder =
+              getMethodOrDie(builderClass, "get" + camelCaseName + "Value", int.class);
+          setRepeatedValueMethod =
+              getMethodOrDie(builderClass, "set" + camelCaseName + "Value", int.class, int.class);
+          addRepeatedValueMethod =
+              getMethodOrDie(builderClass, "add" + camelCaseName + "Value", int.class);
+        }
+      }
+
+      private final EnumDescriptor enumDescriptor;
+
+      private final Method valueOfMethod;
+      private final Method getValueDescriptorMethod;
+
+      private final boolean supportUnknownEnumValue;
+
+      private Method getRepeatedValueMethod;
+      private Method getRepeatedValueMethodBuilder;
+      private Method setRepeatedValueMethod;
+      private Method addRepeatedValueMethod;
+
+      @Override
+      public Object get(final FlattenedGeneratedMessageV3 message) {
+        final List<Object> newList = new ArrayList<>();
+        final int size = getRepeatedCount(message);
+        for (int i = 0; i < size; i++) {
+          newList.add(getRepeated(message, i));
+        }
+        return Collections.unmodifiableList(newList);
+      }
+
+      @Override
+      public Object get(final FlattenedGeneratedMessageV3.Builder<?> builder) {
+        final List<Object> newList = new ArrayList<>();
+        final int size = getRepeatedCount(builder);
+        for (int i = 0; i < size; i++) {
+          newList.add(getRepeated(builder, i));
+        }
+        return Collections.unmodifiableList(newList);
+      }
+
+      @Override
+      public Object getRepeated(final FlattenedGeneratedMessageV3 message, final int index) {
+        if (supportUnknownEnumValue) {
+          int value = (Integer) invokeOrDie(getRepeatedValueMethod, message, index);
+          return enumDescriptor.findValueByNumberCreatingIfUnknown(value);
+        }
+        return invokeOrDie(getValueDescriptorMethod, super.getRepeated(message, index));
+      }
+
+      @Override
+      public Object getRepeated(final FlattenedGeneratedMessageV3.Builder<?> builder, final int index) {
+        if (supportUnknownEnumValue) {
+          int value = (Integer) invokeOrDie(getRepeatedValueMethodBuilder, builder, index);
+          return enumDescriptor.findValueByNumberCreatingIfUnknown(value);
+        }
+        return invokeOrDie(getValueDescriptorMethod, super.getRepeated(builder, index));
+      }
+
+      @Override
+      public void setRepeated(final Builder<?> builder, final int index, final Object value) {
+        if (supportUnknownEnumValue) {
+          // TODO: remove the unused variable
+          Object unused =
+              invokeOrDie(
+                  setRepeatedValueMethod,
+                  builder,
+                  index,
+                  ((EnumValueDescriptor) value).getNumber());
+          return;
+        }
+        super.setRepeated(builder, index, invokeOrDie(valueOfMethod, null, value));
+      }
+
+      @Override
+      public void addRepeated(final Builder<?> builder, final Object value) {
+        if (supportUnknownEnumValue) {
+          // TODO: remove the unused variable
+          Object unused =
+              invokeOrDie(
+                  addRepeatedValueMethod, builder, ((EnumValueDescriptor) value).getNumber());
+          return;
+        }
+        super.addRepeated(builder, invokeOrDie(valueOfMethod, null, value));
+      }
+    }
+
+    // ---------------------------------------------------------------
+
+    /**
+     * Field accessor for string fields.
+     *
+     * <p>This class makes getFooBytes() and setFooBytes() available for reflection API so that
+     * reflection based serialize/parse functions can access the raw bytes of the field to preserve
+     * non-UTF8 bytes in the string.
+     *
+     * <p>This ensures the serialize/parse round-trip safety, which is important for servers which
+     * forward messages.
+     */
+    private static final class SingularStringFieldAccessor extends SingularFieldAccessor {
+      SingularStringFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends FlattenedGeneratedMessageV3> messageClass,
+          final Class<? extends Builder<?>> builderClass,
+          final String containingOneofCamelCaseName) {
+        super(descriptor, camelCaseName, messageClass, builderClass, containingOneofCamelCaseName);
+        getBytesMethod = getMethodOrDie(messageClass, "get" + camelCaseName + "Bytes");
+        setBytesMethodBuilder =
+            getMethodOrDie(builderClass, "set" + camelCaseName + "Bytes", ByteString.class);
+      }
+
+      private final Method getBytesMethod;
+      private final Method setBytesMethodBuilder;
+
+      @Override
+      public Object getRaw(final FlattenedGeneratedMessageV3 message) {
+        return invokeOrDie(getBytesMethod, message);
+      }
+
+      @Override
+      public void set(FlattenedGeneratedMessageV3.Builder<?> builder, Object value) {
+        if (value instanceof ByteString) {
+          // TODO: remove the unused variable
+          Object unused = invokeOrDie(setBytesMethodBuilder, builder, value);
+        } else {
+          super.set(builder, value);
+        }
+      }
+    }
+
+    // ---------------------------------------------------------------
+
+    private static final class SingularMessageFieldAccessor extends SingularFieldAccessor {
+      SingularMessageFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends FlattenedGeneratedMessageV3> messageClass,
+          final Class<? extends Builder<?>> builderClass,
+          final String containingOneofCamelCaseName) {
+        super(descriptor, camelCaseName, messageClass, builderClass, containingOneofCamelCaseName);
+
+        newBuilderMethod = getMethodOrDie(type, "newBuilder");
+        getBuilderMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName + "Builder");
+      }
+
+      private final Method newBuilderMethod;
+      private final Method getBuilderMethodBuilder;
+
+      private Object coerceType(final Object value) {
+        if (type.isInstance(value)) {
+          return value;
+        } else {
+          // The value is not the exact right message type.  However, if it
+          // is an alternative implementation of the same type -- e.g. a
+          // DynamicMessage -- we should accept it.  In this case we can make
+          // a copy of the message.
+          return ((Message.Builder) invokeOrDie(newBuilderMethod, null))
+              .mergeFrom((Message) value)
+              .buildPartial();
+        }
+      }
+
+      @Override
+      public void set(final Builder<?> builder, final Object value) {
+        super.set(builder, coerceType(value));
+      }
+
+      @Override
+      public Message.Builder newBuilder() {
+        return (Message.Builder) invokeOrDie(newBuilderMethod, null);
+      }
+
+      @Override
+      public Message.Builder getBuilder(FlattenedGeneratedMessageV3.Builder<?> builder) {
+        return (Message.Builder) invokeOrDie(getBuilderMethodBuilder, builder);
+      }
+    }
+
+    private static final class RepeatedMessageFieldAccessor extends RepeatedFieldAccessor {
+      RepeatedMessageFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends FlattenedGeneratedMessageV3> messageClass,
+          final Class<? extends Builder<?>> builderClass) {
+        super(descriptor, camelCaseName, messageClass, builderClass);
+
+        newBuilderMethod = getMethodOrDie(type, "newBuilder");
+        getBuilderMethodBuilder =
+            getMethodOrDie(builderClass, "get" + camelCaseName + "Builder", Integer.TYPE);
+      }
+
+      private final Method newBuilderMethod;
+      private final Method getBuilderMethodBuilder;
+
+      private Object coerceType(final Object value) {
+        if (type.isInstance(value)) {
+          return value;
+        } else {
+          // The value is not the exact right message type.  However, if it
+          // is an alternative implementation of the same type -- e.g. a
+          // DynamicMessage -- we should accept it.  In this case we can make
+          // a copy of the message.
+          return ((Message.Builder) invokeOrDie(newBuilderMethod, null))
+              .mergeFrom((Message) value)
+              .build();
+        }
+      }
+
+      @Override
+      public void setRepeated(final Builder<?> builder, final int index, final Object value) {
+        super.setRepeated(builder, index, coerceType(value));
+      }
+
+      @Override
+      public void addRepeated(final Builder<?> builder, final Object value) {
+        super.addRepeated(builder, coerceType(value));
+      }
+
+      @Override
+      public Message.Builder newBuilder() {
+        return (Message.Builder) invokeOrDie(newBuilderMethod, null);
+      }
+
+      @Override
+      public Message.Builder getRepeatedBuilder(
+              final FlattenedGeneratedMessageV3.Builder<?> builder, final int index) {
+        return (Message.Builder) invokeOrDie(getBuilderMethodBuilder, builder, index);
+      }
+    }
+  }
+
+  /**
+   * Replaces this object in the output stream with a serialized form. Part of Java's serialization
+   * magic. Generated sub-classes must override this method by calling {@code return
+   * super.writeReplace();}
+   *
+   * @return a SerializedForm of this message
+   */
+  protected Object writeReplace() throws ObjectStreamException {
+    return new SerializedForm(this);
+  }
+
+  /**
+   * Checks that the {@link Extension} is non-Lite and returns it as a {@link GeneratedExtension}.
+   */
+  private static <MessageT extends ExtendableMessage<MessageT>, T>
+      Extension<MessageT, T> checkNotLite(ExtensionLite<MessageT, T> extension) {
+    if (extension.isLite()) {
+      throw new IllegalArgumentException("Expected non-lite extension.");
+    }
+
+    return (Extension<MessageT, T>) extension;
+  }
+
+  protected static boolean isStringEmpty(final Object value) {
+    if (value instanceof String) {
+      return ((String) value).isEmpty();
+    } else {
+      return ((ByteString) value).isEmpty();
+    }
+  }
+
+  protected static int computeStringSize(final int fieldNumber, final Object value) {
+    if (value instanceof String) {
+      return CodedOutputStream.computeStringSize(fieldNumber, (String) value);
+    } else {
+      return CodedOutputStream.computeBytesSize(fieldNumber, (ByteString) value);
+    }
+  }
+
+  protected static int computeStringSizeNoTag(final Object value) {
+    if (value instanceof String) {
+      return CodedOutputStream.computeStringSizeNoTag((String) value);
+    } else {
+      return CodedOutputStream.computeBytesSizeNoTag((ByteString) value);
+    }
+  }
+
+  protected static void writeString(
+      CodedOutputStream output, final int fieldNumber, final Object value) throws IOException {
+    if (value instanceof String) {
+      output.writeString(fieldNumber, (String) value);
+    } else {
+      output.writeBytes(fieldNumber, (ByteString) value);
+    }
+  }
+
+  protected static void writeStringNoTag(CodedOutputStream output, final Object value)
+      throws IOException {
+    if (value instanceof String) {
+      output.writeStringNoTag((String) value);
+    } else {
+      output.writeBytesNoTag((ByteString) value);
+    }
+  }
+
+  protected static <V> void serializeIntegerMapTo(
+      CodedOutputStream out,
+      MapField<Integer, V> field,
+      MapEntry<Integer, V> defaultEntry,
+      int fieldNumber)
+      throws IOException {
+    Map<Integer, V> m = field.getMap();
+    if (!out.isSerializationDeterministic()) {
+      serializeMapTo(out, m, defaultEntry, fieldNumber);
+      return;
+    }
+    // Sorting the unboxed keys and then look up the values during serialization is 2x faster
+    // than sorting map entries with a custom comparator directly.
+    int[] keys = new int[m.size()];
+    int index = 0;
+    for (int k : m.keySet()) {
+      keys[index++] = k;
+    }
+    Arrays.sort(keys);
+    for (int key : keys) {
+      out.writeMessage(
+          fieldNumber, defaultEntry.newBuilderForType().setKey(key).setValue(m.get(key)).build());
+    }
+  }
+
+  protected static <V> void serializeLongMapTo(
+      CodedOutputStream out,
+      MapField<Long, V> field,
+      MapEntry<Long, V> defaultEntry,
+      int fieldNumber)
+      throws IOException {
+    Map<Long, V> m = field.getMap();
+    if (!out.isSerializationDeterministic()) {
+      serializeMapTo(out, m, defaultEntry, fieldNumber);
+      return;
+    }
+
+    long[] keys = new long[m.size()];
+    int index = 0;
+    for (long k : m.keySet()) {
+      keys[index++] = k;
+    }
+    Arrays.sort(keys);
+    for (long key : keys) {
+      out.writeMessage(
+          fieldNumber, defaultEntry.newBuilderForType().setKey(key).setValue(m.get(key)).build());
+    }
+  }
+
+  protected static <V> void serializeStringMapTo(
+      CodedOutputStream out,
+      MapField<String, V> field,
+      MapEntry<String, V> defaultEntry,
+      int fieldNumber)
+      throws IOException {
+    Map<String, V> m = field.getMap();
+    if (!out.isSerializationDeterministic()) {
+      serializeMapTo(out, m, defaultEntry, fieldNumber);
+      return;
+    }
+
+    // Sorting the String keys and then look up the values during serialization is 25% faster than
+    // sorting map entries with a custom comparator directly.
+    String[] keys = new String[m.size()];
+    keys = m.keySet().toArray(keys);
+    Arrays.sort(keys);
+    for (String key : keys) {
+      out.writeMessage(
+          fieldNumber, defaultEntry.newBuilderForType().setKey(key).setValue(m.get(key)).build());
+    }
+  }
+
+  protected static <V> void serializeBooleanMapTo(
+      CodedOutputStream out,
+      MapField<Boolean, V> field,
+      MapEntry<Boolean, V> defaultEntry,
+      int fieldNumber)
+      throws IOException {
+    Map<Boolean, V> m = field.getMap();
+    if (!out.isSerializationDeterministic()) {
+      serializeMapTo(out, m, defaultEntry, fieldNumber);
+      return;
+    }
+    maybeSerializeBooleanEntryTo(out, m, defaultEntry, fieldNumber, false);
+    maybeSerializeBooleanEntryTo(out, m, defaultEntry, fieldNumber, true);
+  }
+
+  private static <V> void maybeSerializeBooleanEntryTo(
+      CodedOutputStream out,
+      Map<Boolean, V> m,
+      MapEntry<Boolean, V> defaultEntry,
+      int fieldNumber,
+      boolean key)
+      throws IOException {
+    if (m.containsKey(key)) {
+      out.writeMessage(
+          fieldNumber, defaultEntry.newBuilderForType().setKey(key).setValue(m.get(key)).build());
+    }
+  }
+
+  /** Serialize the map using the iteration order. */
+  private static <K, V> void serializeMapTo(
+      CodedOutputStream out, Map<K, V> m, MapEntry<K, V> defaultEntry, int fieldNumber)
+      throws IOException {
+    for (Map.Entry<K, V> entry : m.entrySet()) {
+      out.writeMessage(
+          fieldNumber,
+          defaultEntry
+              .newBuilderForType()
+              .setKey(entry.getKey())
+              .setValue(entry.getValue())
+              .build());
+    }
+  }
+}
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/FloatValue.java b/protobuf-api/src/main/java/com/google/protobuf/FloatValue.java
similarity index 94%
rename from protobuf-sdk/src/main/java/com/google/protobuf/FloatValue.java
rename to protobuf-api/src/main/java/com/google/protobuf/FloatValue.java
index 4b4a8d4..b7d2b36 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/FloatValue.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/FloatValue.java
@@ -14,12 +14,12 @@
  * Protobuf type {@code google.protobuf.FloatValue}
  */
 public final class FloatValue extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.FloatValue)
     FloatValueOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use FloatValue.newBuilder() to construct.
-  private FloatValue(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private FloatValue(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private FloatValue() {
@@ -38,7 +38,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.WrappersProto.internal_static_google_protobuf_FloatValue_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -161,20 +161,20 @@ public static com.google.protobuf.FloatValue parseFrom(
   }
   public static com.google.protobuf.FloatValue parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.FloatValue parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.FloatValue parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -182,20 +182,20 @@ public static com.google.protobuf.FloatValue parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.FloatValue parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.FloatValue parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -215,7 +215,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -229,7 +229,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.FloatValue}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.FloatValue)
       com.google.protobuf.FloatValueOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -238,7 +238,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.WrappersProto.internal_static_google_protobuf_FloatValue_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -251,7 +251,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/FloatValueOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/FloatValueOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/FloatValueOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/FloatValueOrBuilder.java
diff --git a/protobuf-api/src/main/java/com/google/protobuf/GeneratedMessageInternal.java b/protobuf-api/src/main/java/com/google/protobuf/GeneratedMessageInternal.java
new file mode 100644
index 0000000..e247677
--- /dev/null
+++ b/protobuf-api/src/main/java/com/google/protobuf/GeneratedMessageInternal.java
@@ -0,0 +1,2986 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+
+package com.google.protobuf;
+
+import com.google.protobuf.Descriptors.Descriptor;
+import com.google.protobuf.Descriptors.EnumDescriptor;
+import com.google.protobuf.Descriptors.EnumValueDescriptor;
+import com.google.protobuf.Descriptors.FieldDescriptor;
+import com.google.protobuf.Descriptors.FileDescriptor;
+import com.google.protobuf.Descriptors.OneofDescriptor;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.ObjectStreamException;
+import java.io.Serializable;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+/**
+ * All generated protocol message classes extend this class. This class implements most of the
+ * Message and Builder interfaces using Java reflection. Users can ignore this class and pretend
+ * that generated messages implement the Message interface directly.
+ *
+ * @author kenton@google.com Kenton Varda
+ */
+abstract class GeneratedMessageInternal extends AbstractMessageInternal implements Serializable {
+  private static final long serialVersionUID = 1L;
+
+  /**
+   * For testing. Allows a test to disable the optimization that avoids using field builders for
+   * nested messages until they are requested. By disabling this optimization, existing tests can be
+   * reused to test the field builders.
+   */
+  protected static boolean alwaysUseFieldBuilders = false;
+
+  /** For use by generated code only. */
+  protected UnknownFieldSet unknownFields;
+
+  protected GeneratedMessageInternal() {
+    unknownFields = UnknownFieldSet.getDefaultInstance();
+  }
+
+  protected GeneratedMessageInternal(Builder<?> builder) {
+    unknownFields = builder.getUnknownFields();
+  }
+
+  @Override
+  public boolean isGenerated() {
+    return true;
+  }
+
+  @Override
+  public Parser<? extends GeneratedMessageInternal> getParserForType() {
+    throw new UnsupportedOperationException("This is supposed to be overridden by subclasses.");
+  }
+
+  /**
+   * For testing. Allows a test to disable the optimization that avoids using field builders for
+   * nested messages until they are requested. By disabling this optimization, existing tests can be
+   * reused to test the field builders. See {@link RepeatedFieldBuilder} and {@link
+   * SingleFieldBuilder}.
+   */
+  static void enableAlwaysUseFieldBuildersForTesting() {
+    alwaysUseFieldBuilders = true;
+  }
+
+  /**
+   * Get the FieldAccessorTable for this type. We can't have the message class pass this in to the
+   * constructor because of bootstrapping trouble with DescriptorProtos.
+   */
+  protected abstract FieldAccessorTable internalGetFieldAccessorTable();
+
+  @Override
+  public Descriptor getDescriptorForType() {
+    return internalGetFieldAccessorTable().descriptor;
+  }
+
+  /**
+   * Internal helper to return a modifiable map containing all the fields. The returned Map is
+   * modifialbe so that the caller can add additional extension fields to implement {@link
+   * #getAllFields()}.
+   *
+   * @param getBytesForString whether to generate ByteString for string fields
+   */
+  private Map<FieldDescriptor, Object> getAllFieldsMutable(boolean getBytesForString) {
+    final TreeMap<FieldDescriptor, Object> result = new TreeMap<FieldDescriptor, Object>();
+    final Descriptor descriptor = internalGetFieldAccessorTable().descriptor;
+    final List<FieldDescriptor> fields = descriptor.getFields();
+
+    for (int i = 0; i < fields.size(); i++) {
+      FieldDescriptor field = fields.get(i);
+      final OneofDescriptor oneofDescriptor = field.getContainingOneof();
+
+      /*
+       * If the field is part of a Oneof, then at maximum one field in the Oneof is set
+       * and it is not repeated. There is no need to iterate through the others.
+       */
+      if (oneofDescriptor != null) {
+        // Skip other fields in the Oneof we know are not set
+        i += oneofDescriptor.getFieldCount() - 1;
+        if (!hasOneof(oneofDescriptor)) {
+          // If no field is set in the Oneof, skip all the fields in the Oneof
+          continue;
+        }
+        // Get the pointer to the only field which is set in the Oneof
+        field = getOneofFieldDescriptor(oneofDescriptor);
+      } else {
+        // If we are not in a Oneof, we need to check if the field is set and if it is repeated
+        if (field.isRepeated()) {
+          final List<?> value = (List<?>) getField(field);
+          if (!value.isEmpty()) {
+            result.put(field, value);
+          }
+          continue;
+        }
+        if (!hasField(field)) {
+          continue;
+        }
+      }
+      // Add the field to the map
+      if (getBytesForString && field.getJavaType() == FieldDescriptor.JavaType.STRING) {
+        result.put(field, getFieldRaw(field));
+      } else {
+        result.put(field, getField(field));
+      }
+    }
+    return result;
+  }
+
+  @Override
+  public boolean isInitialized() {
+    for (final FieldDescriptor field : getDescriptorForType().getFields()) {
+      // Check that all required fields are present.
+      if (field.isRequired()) {
+        if (!hasField(field)) {
+          return false;
+        }
+      }
+      // Check that embedded messages are initialized.
+      if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+        if (field.isRepeated()) {
+          @SuppressWarnings("unchecked")
+          final List<Message> messageList = (List<Message>) getField(field);
+          for (final Message element : messageList) {
+            if (!element.isInitialized()) {
+              return false;
+            }
+          }
+        } else {
+          if (hasField(field) && !((Message) getField(field)).isInitialized()) {
+            return false;
+          }
+        }
+      }
+    }
+
+    return true;
+  }
+
+  @Override
+  public Map<FieldDescriptor, Object> getAllFields() {
+    return Collections.unmodifiableMap(getAllFieldsMutable(/* getBytesForString = */ false));
+  }
+
+  /**
+   * Returns a collection of all the fields in this message which are set and their corresponding
+   * values. A singular ("required" or "optional") field is set iff hasField() returns true for that
+   * field. A "repeated" field is set iff getRepeatedFieldCount() is greater than zero. The values
+   * are exactly what would be returned by calling {@link #getFieldRaw(FieldDescriptor)}
+   * for each field. The map is guaranteed to be a sorted map, so iterating over it will return
+   * fields in order by field number.
+   */
+  Map<FieldDescriptor, Object> getAllFieldsRaw() {
+    return Collections.unmodifiableMap(getAllFieldsMutable(/* getBytesForString = */ true));
+  }
+
+  @Override
+  public boolean hasOneof(final OneofDescriptor oneof) {
+    return internalGetFieldAccessorTable().getOneof(oneof).has(this);
+  }
+
+  @Override
+  public FieldDescriptor getOneofFieldDescriptor(final OneofDescriptor oneof) {
+    return internalGetFieldAccessorTable().getOneof(oneof).get(this);
+  }
+
+  @Override
+  public boolean hasField(final FieldDescriptor field) {
+    return internalGetFieldAccessorTable().getField(field).has(this);
+  }
+
+  @Override
+  public Object getField(final FieldDescriptor field) {
+    return internalGetFieldAccessorTable().getField(field).get(this);
+  }
+
+  /**
+   * Obtains the value of the given field, or the default value if it is not set. For primitive
+   * fields, the boxed primitive value is returned. For enum fields, the EnumValueDescriptor for the
+   * value is returned. For embedded message fields, the sub-message is returned. For repeated
+   * fields, a java.util.List is returned. For present string fields, a ByteString is returned
+   * representing the bytes that the field contains.
+   */
+  Object getFieldRaw(final FieldDescriptor field) {
+    return internalGetFieldAccessorTable().getField(field).getRaw(this);
+  }
+
+  @Override
+  public int getRepeatedFieldCount(final FieldDescriptor field) {
+    return internalGetFieldAccessorTable().getField(field).getRepeatedCount(this);
+  }
+
+  @Override
+  public Object getRepeatedField(final FieldDescriptor field, final int index) {
+    return internalGetFieldAccessorTable().getField(field).getRepeated(this, index);
+  }
+
+  @Override
+  public UnknownFieldSet getUnknownFields() {
+    throw new UnsupportedOperationException("This is supposed to be overridden by subclasses.");
+  }
+
+  /**
+   * Called by subclasses to parse an unknown field.
+   *
+   * @return {@code true} unless the tag is an end-group tag.
+   */
+  protected boolean parseUnknownField(
+      CodedInputStream input,
+      UnknownFieldSet.Builder unknownFields,
+      ExtensionRegistryLite extensionRegistry,
+      int tag)
+      throws IOException {
+    return unknownFields.mergeFieldFrom(tag, input);
+  }
+
+  protected static <M extends Message> M parseWithIOException(Parser<M> parser, InputStream input)
+      throws IOException {
+    try {
+      return parser.parseFrom(input);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  protected static <M extends Message> M parseWithIOException(
+      Parser<M> parser, InputStream input, ExtensionRegistryLite extensions) throws IOException {
+    try {
+      return parser.parseFrom(input, extensions);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  protected static <M extends Message> M parseWithIOException(
+      Parser<M> parser, CodedInputStream input) throws IOException {
+    try {
+      return parser.parseFrom(input);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  protected static <M extends Message> M parseWithIOException(
+      Parser<M> parser, CodedInputStream input, ExtensionRegistryLite extensions)
+      throws IOException {
+    try {
+      return parser.parseFrom(input, extensions);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  protected static <M extends Message> M parseDelimitedWithIOException(
+      Parser<M> parser, InputStream input) throws IOException {
+    try {
+      return parser.parseDelimitedFrom(input);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  protected static <M extends Message> M parseDelimitedWithIOException(
+      Parser<M> parser, InputStream input, ExtensionRegistryLite extensions) throws IOException {
+    try {
+      return parser.parseDelimitedFrom(input, extensions);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  @Override
+  public void writeTo(final CodedOutputStream output) throws IOException {
+    MessageReflection.writeMessageTo(this, getAllFieldsRaw(), output, false);
+  }
+
+  @Override
+  public int getSerializedSize() {
+    int size = memoizedSize;
+    if (size != -1) {
+      return size;
+    }
+
+    memoizedSize = MessageReflection.getSerializedSize(this, getAllFieldsRaw());
+    return memoizedSize;
+  }
+
+  /** Used by parsing constructors in generated classes. */
+  protected void makeExtensionsImmutable() {
+    // Noop for messages without extensions.
+  }
+
+  /**
+   * TODO: remove this after b/29368482 is fixed. We need to move this interface to
+   * AbstractMessage in order to versioning GeneratedMessageInternal but this move breaks binary
+   * compatibility for AppEngine. After AppEngine is fixed we can exclude this from google3.
+   */
+  protected interface BuilderParent extends AbstractMessageInternal.BuilderParent {}
+
+  /** TODO: remove this together with GeneratedMessageInternal.BuilderParent. */
+  protected abstract Message.Builder newBuilderForType(BuilderParent parent);
+
+  public Message.Builder newBuilderForType(final Message.BuilderParent parent) {
+    return newBuilderForType(
+        new BuilderParent() {
+          @Override
+          public void markDirty() {
+            parent.markDirty();
+          }
+        });
+  }
+
+  @SuppressWarnings("unchecked")
+  public abstract static class Builder<BuilderType extends Builder<BuilderType>>
+      extends AbstractMessageInternal.Builder<BuilderType> {
+
+    private BuilderParent builderParent;
+
+    private BuilderParentImpl meAsParent;
+
+    // Indicates that we've built a message and so we are now obligated
+    // to dispatch dirty invalidations. See GeneratedMessageInternal.BuilderListener.
+    private boolean isClean;
+
+    private UnknownFieldSet unknownFields = UnknownFieldSet.getDefaultInstance();
+
+    protected Builder() {
+      this(null);
+    }
+
+    protected Builder(BuilderParent builderParent) {
+      this.builderParent = builderParent;
+    }
+
+    @Override
+    public boolean isGenerated() {
+      return true;
+    }
+
+    @Override
+    public void dispose() {
+      builderParent = null;
+    }
+
+    /** Called by the subclass when a message is built. */
+    protected void onBuilt() {
+      if (builderParent != null) {
+        markClean();
+      }
+    }
+
+    /**
+     * Called by the subclass or a builder to notify us that a message was built and may be cached
+     * and therefore invalidations are needed.
+     */
+    @Override
+    public void markClean() {
+      this.isClean = true;
+    }
+
+    /**
+     * Gets whether invalidations are needed
+     *
+     * @return whether invalidations are needed
+     */
+    protected boolean isClean() {
+      return isClean;
+    }
+
+    @Override
+    public BuilderType clone() {
+      BuilderType builder = (BuilderType) getDefaultInstanceForType().newBuilderForType();
+      builder.mergeFrom(buildPartial());
+      return builder;
+    }
+
+    /**
+     * Called by the initialization and clear code paths to allow subclasses to reset any of their
+     * builtin fields back to the initial values.
+     */
+    @Override
+    public BuilderType clear() {
+      unknownFields = UnknownFieldSet.getDefaultInstance();
+      onChanged();
+      return (BuilderType) this;
+    }
+
+    /**
+     * Get the FieldAccessorTable for this type. We can't have the message class pass this in to the
+     * constructor because of bootstrapping trouble with DescriptorProtos.
+     */
+    protected abstract FieldAccessorTable internalGetFieldAccessorTable();
+
+    @Override
+    public Descriptor getDescriptorForType() {
+      return internalGetFieldAccessorTable().descriptor;
+    }
+
+    @Override
+    public Map<FieldDescriptor, Object> getAllFields() {
+      return Collections.unmodifiableMap(getAllFieldsMutable());
+    }
+
+    /** Internal helper which returns a mutable map. */
+    private Map<FieldDescriptor, Object> getAllFieldsMutable() {
+      final TreeMap<FieldDescriptor, Object> result = new TreeMap<FieldDescriptor, Object>();
+      final Descriptor descriptor = internalGetFieldAccessorTable().descriptor;
+      final List<FieldDescriptor> fields = descriptor.getFields();
+
+      for (int i = 0; i < fields.size(); i++) {
+        FieldDescriptor field = fields.get(i);
+        final OneofDescriptor oneofDescriptor = field.getContainingOneof();
+
+        /*
+         * If the field is part of a Oneof, then at maximum one field in the Oneof is set
+         * and it is not repeated. There is no need to iterate through the others.
+         */
+        if (oneofDescriptor != null) {
+          // Skip other fields in the Oneof we know are not set
+          i += oneofDescriptor.getFieldCount() - 1;
+          if (!hasOneof(oneofDescriptor)) {
+            // If no field is set in the Oneof, skip all the fields in the Oneof
+            continue;
+          }
+          // Get the pointer to the only field which is set in the Oneof
+          field = getOneofFieldDescriptor(oneofDescriptor);
+        } else {
+          // If we are not in a Oneof, we need to check if the field is set and if it is repeated
+          if (field.isRepeated()) {
+            final List<?> value = (List<?>) getField(field);
+            if (!value.isEmpty()) {
+              result.put(field, value);
+            }
+            continue;
+          }
+          if (!hasField(field)) {
+            continue;
+          }
+        }
+        // Add the field to the map
+        result.put(field, getField(field));
+      }
+      return result;
+    }
+
+    @Override
+    public Message.Builder newBuilderForField(final FieldDescriptor field) {
+      return internalGetFieldAccessorTable().getField(field).newBuilder();
+    }
+
+    @Override
+    public Message.Builder getFieldBuilder(final FieldDescriptor field) {
+      return internalGetFieldAccessorTable().getField(field).getBuilder(this);
+    }
+
+    @Override
+    public Message.Builder getRepeatedFieldBuilder(final FieldDescriptor field, int index) {
+      return internalGetFieldAccessorTable().getField(field).getRepeatedBuilder(this, index);
+    }
+
+    @Override
+    public boolean hasOneof(final OneofDescriptor oneof) {
+      return internalGetFieldAccessorTable().getOneof(oneof).has(this);
+    }
+
+    @Override
+    public FieldDescriptor getOneofFieldDescriptor(final OneofDescriptor oneof) {
+      return internalGetFieldAccessorTable().getOneof(oneof).get(this);
+    }
+
+    @Override
+    public boolean hasField(final FieldDescriptor field) {
+      return internalGetFieldAccessorTable().getField(field).has(this);
+    }
+
+    @Override
+    public Object getField(final FieldDescriptor field) {
+      Object object = internalGetFieldAccessorTable().getField(field).get(this);
+      if (field.isRepeated()) {
+        // The underlying list object is still modifiable at this point.
+        // Make sure not to expose the modifiable list to the caller.
+        return Collections.unmodifiableList((List) object);
+      } else {
+        return object;
+      }
+    }
+
+    @Override
+    public BuilderType setField(final FieldDescriptor field, final Object value) {
+      internalGetFieldAccessorTable().getField(field).set(this, value);
+      return (BuilderType) this;
+    }
+
+    @Override
+    public BuilderType clearField(final FieldDescriptor field) {
+      internalGetFieldAccessorTable().getField(field).clear(this);
+      return (BuilderType) this;
+    }
+
+    @Override
+    public BuilderType clearOneof(final OneofDescriptor oneof) {
+      internalGetFieldAccessorTable().getOneof(oneof).clear(this);
+      return (BuilderType) this;
+    }
+
+    @Override
+    public int getRepeatedFieldCount(final FieldDescriptor field) {
+      return internalGetFieldAccessorTable().getField(field).getRepeatedCount(this);
+    }
+
+    @Override
+    public Object getRepeatedField(final FieldDescriptor field, final int index) {
+      return internalGetFieldAccessorTable().getField(field).getRepeated(this, index);
+    }
+
+    @Override
+    public BuilderType setRepeatedField(
+        final FieldDescriptor field, final int index, final Object value) {
+      internalGetFieldAccessorTable().getField(field).setRepeated(this, index, value);
+      return (BuilderType) this;
+    }
+
+    @Override
+    public BuilderType addRepeatedField(final FieldDescriptor field, final Object value) {
+      internalGetFieldAccessorTable().getField(field).addRepeated(this, value);
+      return (BuilderType) this;
+    }
+
+    @Override
+    public BuilderType setUnknownFields(final UnknownFieldSet unknownFields) {
+      this.unknownFields = unknownFields;
+      onChanged();
+      return (BuilderType) this;
+    }
+
+    @Override
+    public BuilderType mergeUnknownFields(final UnknownFieldSet unknownFields) {
+      this.unknownFields =
+          UnknownFieldSet.newBuilder(this.unknownFields).mergeFrom(unknownFields).build();
+      onChanged();
+      return (BuilderType) this;
+    }
+
+    @Override
+    public boolean isInitialized() {
+      for (final FieldDescriptor field : getDescriptorForType().getFields()) {
+        // Check that all required fields are present.
+        if (field.isRequired()) {
+          if (!hasField(field)) {
+            return false;
+          }
+        }
+        // Check that embedded messages are initialized.
+        if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+          if (field.isRepeated()) {
+            @SuppressWarnings("unchecked")
+            final List<Message> messageList = (List<Message>) getField(field);
+            for (final Message element : messageList) {
+              if (!element.isInitialized()) {
+                return false;
+              }
+            }
+          } else {
+            if (hasField(field) && !((Message) getField(field)).isInitialized()) {
+              return false;
+            }
+          }
+        }
+      }
+      return true;
+    }
+
+    @Override
+    public final UnknownFieldSet getUnknownFields() {
+      return unknownFields;
+    }
+
+    /**
+     * Called by subclasses to parse an unknown field.
+     *
+     * @return {@code true} unless the tag is an end-group tag.
+     */
+    protected boolean parseUnknownField(
+        final CodedInputStream input,
+        final UnknownFieldSet.Builder unknownFields,
+        final ExtensionRegistryLite extensionRegistry,
+        final int tag)
+        throws IOException {
+      return unknownFields.mergeFieldFrom(tag, input);
+    }
+
+    /**
+     * Implementation of {@link BuilderParent} for giving to our children. This small inner class
+     * makes it so we don't publicly expose the BuilderParent methods.
+     */
+    private class BuilderParentImpl implements BuilderParent {
+
+      @Override
+      public void markDirty() {
+        onChanged();
+      }
+    }
+
+    /**
+     * Gets the {@link BuilderParent} for giving to our children.
+     *
+     * @return The builder parent for our children.
+     */
+    protected BuilderParent getParentForChildren() {
+      if (meAsParent == null) {
+        meAsParent = new BuilderParentImpl();
+      }
+      return meAsParent;
+    }
+
+    /**
+     * Called when a the builder or one of its nested children has changed and any parent should be
+     * notified of its invalidation.
+     */
+    protected final void onChanged() {
+      if (isClean && builderParent != null) {
+        builderParent.markDirty();
+
+        // Don't keep dispatching invalidations until build is called again.
+        isClean = false;
+      }
+    }
+
+    /**
+     * Gets the map field with the given field number. This method should be overridden in the
+     * generated message class if the message contains map fields.
+     *
+     * <p>Unlike other field types, reflection support for map fields can't be implemented based on
+     * generated public API because we need to access a map field as a list in reflection API but
+     * the generated API only allows us to access it as a map. This method returns the underlying
+     * map field directly and thus enables us to access the map field as a list.
+     */
+    @SuppressWarnings({"unused", "rawtypes"})
+    protected MapField internalGetMapField(int fieldNumber) {
+      // Note that we can't use descriptor names here because this method will
+      // be called when descriptor is being initialized.
+      throw new RuntimeException("No map fields found in " + getClass().getName());
+    }
+
+    /** Like {@link #internalGetMapField} but return a mutable version. */
+    @SuppressWarnings({"unused", "rawtypes"})
+    protected MapField internalGetMutableMapField(int fieldNumber) {
+      // Note that we can't use descriptor names here because this method will
+      // be called when descriptor is being initialized.
+      throw new RuntimeException("No map fields found in " + getClass().getName());
+    }
+  }
+
+  // =================================================================
+  // Extensions-related stuff
+
+  public interface ExtendableMessageOrBuilder<MessageType extends ExtendableMessage>
+      extends MessageOrBuilder {
+    // Re-define for return type covariance.
+    @Override
+    Message getDefaultInstanceForType();
+
+    /** Check if a singular extension is present. */
+    <Type> boolean hasExtension(ExtensionLite<MessageType, Type> extension);
+
+    /** Get the number of elements in a repeated extension. */
+    <Type> int getExtensionCount(ExtensionLite<MessageType, List<Type>> extension);
+
+    /** Get the value of an extension. */
+    <Type> Type getExtension(ExtensionLite<MessageType, Type> extension);
+
+    /** Get one element of a repeated extension. */
+    <Type> Type getExtension(ExtensionLite<MessageType, List<Type>> extension, int index);
+
+    /** Check if a singular extension is present. */
+    <Type> boolean hasExtension(Extension<MessageType, Type> extension);
+    /** Check if a singular extension is present. */
+    <Type> boolean hasExtension(GeneratedExtension<MessageType, Type> extension);
+    /** Get the number of elements in a repeated extension. */
+    <Type> int getExtensionCount(Extension<MessageType, List<Type>> extension);
+    /** Get the number of elements in a repeated extension. */
+    <Type> int getExtensionCount(GeneratedExtension<MessageType, List<Type>> extension);
+    /** Get the value of an extension. */
+    <Type> Type getExtension(Extension<MessageType, Type> extension);
+    /** Get the value of an extension. */
+    <Type> Type getExtension(GeneratedExtension<MessageType, Type> extension);
+    /** Get one element of a repeated extension. */
+    <Type> Type getExtension(Extension<MessageType, List<Type>> extension, int index);
+    /** Get one element of a repeated extension. */
+    <Type> Type getExtension(GeneratedExtension<MessageType, List<Type>> extension, int index);
+  }
+
+  /**
+   * Generated message classes for message types that contain extension ranges subclass this.
+   *
+   * <p>This class implements type-safe accessors for extensions. They implement all the same
+   * operations that you can do with normal fields -- e.g. "has", "get", and "getCount" -- but for
+   * extensions. The extensions are identified using instances of the class {@link
+   * GeneratedExtension}; the protocol compiler generates a static instance of this class for every
+   * extension in its input. Through the magic of generics, all is made type-safe.
+   *
+   * <p>For example, imagine you have the {@code .proto} file:
+   *
+   * <pre>
+   * option java_class = "MyProto";
+   *
+   * message Foo {
+   *   extensions 1000 to max;
+   * }
+   *
+   * extend Foo {
+   *   optional int32 bar;
+   * }
+   * </pre>
+   *
+   * <p>Then you might write code like:
+   *
+   * <pre>
+   * MyProto.Foo foo = getFoo();
+   * int i = foo.getExtension(MyProto.bar);
+   * </pre>
+   *
+   * <p>See also {@link ExtendableBuilder}.
+   */
+  public abstract static class ExtendableMessage<MessageType extends ExtendableMessage>
+      extends GeneratedMessageInternal implements ExtendableMessageOrBuilder<MessageType> {
+
+    private static final long serialVersionUID = 1L;
+
+    private final FieldSet<FieldDescriptor> extensions;
+
+    protected ExtendableMessage() {
+      this.extensions = FieldSet.newFieldSet();
+    }
+
+    protected ExtendableMessage(ExtendableBuilder<MessageType, ?> builder) {
+      super(builder);
+      this.extensions = builder.buildExtensions();
+    }
+
+    private void verifyExtensionContainingType(final Extension<MessageType, ?> extension) {
+      if (extension.getDescriptor().getContainingType() != getDescriptorForType()) {
+        // This can only happen if someone uses unchecked operations.
+        throw new IllegalArgumentException(
+            "Extension is for type \""
+                + extension.getDescriptor().getContainingType().getFullName()
+                + "\" which does not match message type \""
+                + getDescriptorForType().getFullName()
+                + "\".");
+      }
+    }
+
+    /** Check if a singular extension is present. */
+    @Override
+    @SuppressWarnings("unchecked")
+    public final <Type> boolean hasExtension(final ExtensionLite<MessageType, Type> extensionLite) {
+      Extension<MessageType, Type> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      return extensions.hasField(extension.getDescriptor());
+    }
+
+    /** Get the number of elements in a repeated extension. */
+    @Override
+    @SuppressWarnings("unchecked")
+    public final <Type> int getExtensionCount(
+        final ExtensionLite<MessageType, List<Type>> extensionLite) {
+      Extension<MessageType, List<Type>> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      final FieldDescriptor descriptor = extension.getDescriptor();
+      return extensions.getRepeatedFieldCount(descriptor);
+    }
+
+    /** Get the value of an extension. */
+    @Override
+    @SuppressWarnings("unchecked")
+    public final <Type> Type getExtension(final ExtensionLite<MessageType, Type> extensionLite) {
+      Extension<MessageType, Type> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      FieldDescriptor descriptor = extension.getDescriptor();
+      final Object value = extensions.getField(descriptor);
+      if (value == null) {
+        if (descriptor.isRepeated()) {
+          return (Type) Collections.emptyList();
+        } else if (descriptor.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+          return (Type) extension.getMessageDefaultInstance();
+        } else {
+          return (Type) extension.fromReflectionType(descriptor.getDefaultValue());
+        }
+      } else {
+        return (Type) extension.fromReflectionType(value);
+      }
+    }
+
+    /** Get one element of a repeated extension. */
+    @Override
+    @SuppressWarnings("unchecked")
+    public final <Type> Type getExtension(
+        final ExtensionLite<MessageType, List<Type>> extensionLite, final int index) {
+      Extension<MessageType, List<Type>> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      FieldDescriptor descriptor = extension.getDescriptor();
+      return (Type)
+          extension.singularFromReflectionType(extensions.getRepeatedField(descriptor, index));
+    }
+
+    /** Check if a singular extension is present. */
+    @Override
+    public final <Type> boolean hasExtension(final Extension<MessageType, Type> extension) {
+      return hasExtension((ExtensionLite<MessageType, Type>) extension);
+    }
+    /** Check if a singular extension is present. */
+    @Override
+    public final <Type> boolean hasExtension(
+        final GeneratedExtension<MessageType, Type> extension) {
+      return hasExtension((ExtensionLite<MessageType, Type>) extension);
+    }
+    /** Get the number of elements in a repeated extension. */
+    @Override
+    public final <Type> int getExtensionCount(final Extension<MessageType, List<Type>> extension) {
+      return getExtensionCount((ExtensionLite<MessageType, List<Type>>) extension);
+    }
+    /** Get the number of elements in a repeated extension. */
+    @Override
+    public final <Type> int getExtensionCount(
+        final GeneratedExtension<MessageType, List<Type>> extension) {
+      return getExtensionCount((ExtensionLite<MessageType, List<Type>>) extension);
+    }
+    /** Get the value of an extension. */
+    @Override
+    public final <Type> Type getExtension(final Extension<MessageType, Type> extension) {
+      return getExtension((ExtensionLite<MessageType, Type>) extension);
+    }
+    /** Get the value of an extension. */
+    @Override
+    public final <Type> Type getExtension(final GeneratedExtension<MessageType, Type> extension) {
+      return getExtension((ExtensionLite<MessageType, Type>) extension);
+    }
+    /** Get one element of a repeated extension. */
+    @Override
+    public final <Type> Type getExtension(
+        final Extension<MessageType, List<Type>> extension, final int index) {
+      return getExtension((ExtensionLite<MessageType, List<Type>>) extension, index);
+    }
+    /** Get one element of a repeated extension. */
+    @Override
+    public final <Type> Type getExtension(
+        final GeneratedExtension<MessageType, List<Type>> extension, final int index) {
+      return getExtension((ExtensionLite<MessageType, List<Type>>) extension, index);
+    }
+
+    /** Called by subclasses to check if all extensions are initialized. */
+    protected boolean extensionsAreInitialized() {
+      return extensions.isInitialized();
+    }
+
+    @Override
+    public boolean isInitialized() {
+      return super.isInitialized() && extensionsAreInitialized();
+    }
+
+    @Override
+    protected boolean parseUnknownField(
+        CodedInputStream input,
+        UnknownFieldSet.Builder unknownFields,
+        ExtensionRegistryLite extensionRegistry,
+        int tag)
+        throws IOException {
+      return MessageReflection.mergeFieldFrom(
+          input,
+          unknownFields,
+          extensionRegistry,
+          getDescriptorForType(),
+          new MessageReflection.ExtensionAdapter(extensions),
+          tag);
+    }
+
+    /** Used by parsing constructors in generated classes. */
+    @Override
+    protected void makeExtensionsImmutable() {
+      extensions.makeImmutable();
+    }
+
+    /**
+     * Used by subclasses to serialize extensions. Extension ranges may be interleaved with field
+     * numbers, but we must write them in canonical (sorted by field number) order. ExtensionWriter
+     * helps us write individual ranges of extensions at once.
+     */
+    protected class ExtensionWriter {
+      // Imagine how much simpler this code would be if Java iterators had
+      // a way to get the next element without advancing the iterator.
+
+      private final Iterator<Map.Entry<FieldDescriptor, Object>> iter = extensions.iterator();
+      private Map.Entry<FieldDescriptor, Object> next;
+      private final boolean messageSetWireFormat;
+
+      private ExtensionWriter(final boolean messageSetWireFormat) {
+        if (iter.hasNext()) {
+          next = iter.next();
+        }
+        this.messageSetWireFormat = messageSetWireFormat;
+      }
+
+      public void writeUntil(final int end, final CodedOutputStream output) throws IOException {
+        while (next != null && next.getKey().getNumber() < end) {
+          FieldDescriptor descriptor = next.getKey();
+          if (messageSetWireFormat
+              && descriptor.getLiteJavaType() == WireFormat.JavaType.MESSAGE
+              && !descriptor.isRepeated()) {
+            if (next instanceof LazyField.LazyEntry<?>) {
+              output.writeRawMessageSetExtension(
+                  descriptor.getNumber(),
+                  ((LazyField.LazyEntry<?>) next).getField().toByteString());
+            } else {
+              output.writeMessageSetExtension(descriptor.getNumber(), (Message) next.getValue());
+            }
+          } else {
+            // TODO: Taken care of following code, it may cause
+            // problem when we use LazyField for normal fields/extensions.
+            // Due to the optional field can be duplicated at the end of
+            // serialized bytes, which will make the serialized size change
+            // after lazy field parsed. So when we use LazyField globally,
+            // we need to change the following write method to write cached
+            // bytes directly rather than write the parsed message.
+            FieldSet.writeField(descriptor, next.getValue(), output);
+          }
+          if (iter.hasNext()) {
+            next = iter.next();
+          } else {
+            next = null;
+          }
+        }
+      }
+    }
+
+    protected ExtensionWriter newExtensionWriter() {
+      return new ExtensionWriter(false);
+    }
+
+    protected ExtensionWriter newMessageSetExtensionWriter() {
+      return new ExtensionWriter(true);
+    }
+
+    /** Called by subclasses to compute the size of extensions. */
+    protected int extensionsSerializedSize() {
+      return extensions.getSerializedSize();
+    }
+
+    protected int extensionsSerializedSizeAsMessageSet() {
+      return extensions.getMessageSetSerializedSize();
+    }
+
+    // ---------------------------------------------------------------
+    // Reflection
+
+    protected Map<FieldDescriptor, Object> getExtensionFields() {
+      return extensions.getAllFields();
+    }
+
+    @Override
+    public Map<FieldDescriptor, Object> getAllFields() {
+      final Map<FieldDescriptor, Object> result =
+          super.getAllFieldsMutable(/* getBytesForString = */ false);
+      result.putAll(getExtensionFields());
+      return Collections.unmodifiableMap(result);
+    }
+
+    @Override
+    public Map<FieldDescriptor, Object> getAllFieldsRaw() {
+      final Map<FieldDescriptor, Object> result =
+          super.getAllFieldsMutable(/* getBytesForString = */ false);
+      result.putAll(getExtensionFields());
+      return Collections.unmodifiableMap(result);
+    }
+
+    @Override
+    public boolean hasField(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        return extensions.hasField(field);
+      } else {
+        return super.hasField(field);
+      }
+    }
+
+    @Override
+    public Object getField(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        final Object value = extensions.getField(field);
+        if (value == null) {
+          if (field.isRepeated()) {
+            return Collections.emptyList();
+          } else if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+            // Lacking an ExtensionRegistry, we have no way to determine the
+            // extension's real type, so we return a DynamicMessage.
+            return DynamicMessage.getDefaultInstance(field.getMessageType());
+          } else {
+            return field.getDefaultValue();
+          }
+        } else {
+          return value;
+        }
+      } else {
+        return super.getField(field);
+      }
+    }
+
+    @Override
+    public int getRepeatedFieldCount(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        return extensions.getRepeatedFieldCount(field);
+      } else {
+        return super.getRepeatedFieldCount(field);
+      }
+    }
+
+    @Override
+    public Object getRepeatedField(final FieldDescriptor field, final int index) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        return extensions.getRepeatedField(field, index);
+      } else {
+        return super.getRepeatedField(field, index);
+      }
+    }
+
+    private void verifyContainingType(final FieldDescriptor field) {
+      if (field.getContainingType() != getDescriptorForType()) {
+        throw new IllegalArgumentException("FieldDescriptor does not match message type.");
+      }
+    }
+  }
+
+  /**
+   * Generated message builders for message types that contain extension ranges subclass this.
+   *
+   * <p>This class implements type-safe accessors for extensions. They implement all the same
+   * operations that you can do with normal fields -- e.g. "get", "set", and "add" -- but for
+   * extensions. The extensions are identified using instances of the class {@link
+   * GeneratedExtension}; the protocol compiler generates a static instance of this class for every
+   * extension in its input. Through the magic of generics, all is made type-safe.
+   *
+   * <p>For example, imagine you have the {@code .proto} file:
+   *
+   * <pre>
+   * option java_class = "MyProto";
+   *
+   * message Foo {
+   *   extensions 1000 to max;
+   * }
+   *
+   * extend Foo {
+   *   optional int32 bar;
+   * }
+   * </pre>
+   *
+   * <p>Then you might write code like:
+   *
+   * <pre>
+   * MyProto.Foo foo =
+   *   MyProto.Foo.newBuilder()
+   *     .setExtension(MyProto.bar, 123)
+   *     .build();
+   * </pre>
+   *
+   * <p>See also {@link ExtendableMessage}.
+   */
+  @SuppressWarnings("unchecked")
+  public abstract static class ExtendableBuilder<
+          MessageType extends ExtendableMessage,
+          BuilderType extends ExtendableBuilder<MessageType, BuilderType>>
+      extends Builder<BuilderType> implements ExtendableMessageOrBuilder<MessageType> {
+
+    private FieldSet<FieldDescriptor> extensions = FieldSet.emptySet();
+
+    protected ExtendableBuilder() {}
+
+    protected ExtendableBuilder(BuilderParent parent) {
+      super(parent);
+    }
+
+    // For immutable message conversion.
+    void internalSetExtensionSet(FieldSet<FieldDescriptor> extensions) {
+      this.extensions = extensions;
+    }
+
+    @Override
+    public BuilderType clear() {
+      extensions = FieldSet.emptySet();
+      return super.clear();
+    }
+
+    // This is implemented here only to work around an apparent bug in the
+    // Java compiler and/or build system.  See bug #1898463.  The mere presence
+    // of this clone() implementation makes it go away.
+    @Override
+    public BuilderType clone() {
+      return super.clone();
+    }
+
+    private void ensureExtensionsIsMutable() {
+      if (extensions.isImmutable()) {
+        extensions = extensions.clone();
+      }
+    }
+
+    private void verifyExtensionContainingType(final Extension<MessageType, ?> extension) {
+      if (extension.getDescriptor().getContainingType() != getDescriptorForType()) {
+        // This can only happen if someone uses unchecked operations.
+        throw new IllegalArgumentException(
+            "Extension is for type \""
+                + extension.getDescriptor().getContainingType().getFullName()
+                + "\" which does not match message type \""
+                + getDescriptorForType().getFullName()
+                + "\".");
+      }
+    }
+
+    /** Check if a singular extension is present. */
+    @Override
+    public final <Type> boolean hasExtension(final ExtensionLite<MessageType, Type> extensionLite) {
+      Extension<MessageType, Type> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      return extensions.hasField(extension.getDescriptor());
+    }
+
+    /** Get the number of elements in a repeated extension. */
+    @Override
+    public final <Type> int getExtensionCount(
+        final ExtensionLite<MessageType, List<Type>> extensionLite) {
+      Extension<MessageType, List<Type>> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      final FieldDescriptor descriptor = extension.getDescriptor();
+      return extensions.getRepeatedFieldCount(descriptor);
+    }
+
+    /** Get the value of an extension. */
+    @Override
+    public final <Type> Type getExtension(final ExtensionLite<MessageType, Type> extensionLite) {
+      Extension<MessageType, Type> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      FieldDescriptor descriptor = extension.getDescriptor();
+      final Object value = extensions.getField(descriptor);
+      if (value == null) {
+        if (descriptor.isRepeated()) {
+          return (Type) Collections.emptyList();
+        } else if (descriptor.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+          return (Type) extension.getMessageDefaultInstance();
+        } else {
+          return (Type) extension.fromReflectionType(descriptor.getDefaultValue());
+        }
+      } else {
+        return (Type) extension.fromReflectionType(value);
+      }
+    }
+
+    /** Get one element of a repeated extension. */
+    @Override
+    public final <Type> Type getExtension(
+        final ExtensionLite<MessageType, List<Type>> extensionLite, final int index) {
+      Extension<MessageType, List<Type>> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      FieldDescriptor descriptor = extension.getDescriptor();
+      return (Type)
+          extension.singularFromReflectionType(extensions.getRepeatedField(descriptor, index));
+    }
+
+    /** Set the value of an extension. */
+    public final <Type> BuilderType setExtension(
+        final ExtensionLite<MessageType, Type> extensionLite, final Type value) {
+      Extension<MessageType, Type> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      ensureExtensionsIsMutable();
+      final FieldDescriptor descriptor = extension.getDescriptor();
+      extensions.setField(descriptor, extension.toReflectionType(value));
+      onChanged();
+      return (BuilderType) this;
+    }
+
+    /** Set the value of one element of a repeated extension. */
+    public final <Type> BuilderType setExtension(
+        final ExtensionLite<MessageType, List<Type>> extensionLite,
+        final int index,
+        final Type value) {
+      Extension<MessageType, List<Type>> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      ensureExtensionsIsMutable();
+      final FieldDescriptor descriptor = extension.getDescriptor();
+      extensions.setRepeatedField(descriptor, index, extension.singularToReflectionType(value));
+      onChanged();
+      return (BuilderType) this;
+    }
+
+    /** Append a value to a repeated extension. */
+    public final <Type> BuilderType addExtension(
+        final ExtensionLite<MessageType, List<Type>> extensionLite, final Type value) {
+      Extension<MessageType, List<Type>> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      ensureExtensionsIsMutable();
+      final FieldDescriptor descriptor = extension.getDescriptor();
+      extensions.addRepeatedField(descriptor, extension.singularToReflectionType(value));
+      onChanged();
+      return (BuilderType) this;
+    }
+
+    /** Clear an extension. */
+    public final <Type> BuilderType clearExtension(
+        final ExtensionLite<MessageType, ?> extensionLite) {
+      Extension<MessageType, ?> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      ensureExtensionsIsMutable();
+      extensions.clearField(extension.getDescriptor());
+      onChanged();
+      return (BuilderType) this;
+    }
+
+    /** Check if a singular extension is present. */
+    @Override
+    public final <Type> boolean hasExtension(final Extension<MessageType, Type> extension) {
+      return hasExtension((ExtensionLite<MessageType, Type>) extension);
+    }
+    /** Check if a singular extension is present. */
+    @Override
+    public final <Type> boolean hasExtension(
+        final GeneratedExtension<MessageType, Type> extension) {
+      return hasExtension((ExtensionLite<MessageType, Type>) extension);
+    }
+    /** Get the number of elements in a repeated extension. */
+    @Override
+    public final <Type> int getExtensionCount(final Extension<MessageType, List<Type>> extension) {
+      return getExtensionCount((ExtensionLite<MessageType, List<Type>>) extension);
+    }
+    /** Get the number of elements in a repeated extension. */
+    @Override
+    public final <Type> int getExtensionCount(
+        final GeneratedExtension<MessageType, List<Type>> extension) {
+      return getExtensionCount((ExtensionLite<MessageType, List<Type>>) extension);
+    }
+    /** Get the value of an extension. */
+    @Override
+    public final <Type> Type getExtension(final Extension<MessageType, Type> extension) {
+      return getExtension((ExtensionLite<MessageType, Type>) extension);
+    }
+    /** Get the value of an extension. */
+    @Override
+    public final <Type> Type getExtension(final GeneratedExtension<MessageType, Type> extension) {
+      return getExtension((ExtensionLite<MessageType, Type>) extension);
+    }
+    /** Get the value of an extension. */
+    @Override
+    public final <Type> Type getExtension(
+        final Extension<MessageType, List<Type>> extension, final int index) {
+      return getExtension((ExtensionLite<MessageType, List<Type>>) extension, index);
+    }
+    /** Get the value of an extension. */
+    @Override
+    public final <Type> Type getExtension(
+        final GeneratedExtension<MessageType, List<Type>> extension, final int index) {
+      return getExtension((ExtensionLite<MessageType, List<Type>>) extension, index);
+    }
+    /** Set the value of an extension. */
+    public final <Type> BuilderType setExtension(
+        final Extension<MessageType, Type> extension, final Type value) {
+      return setExtension((ExtensionLite<MessageType, Type>) extension, value);
+    }
+    /** Set the value of an extension. */
+    public <Type> BuilderType setExtension(
+        final GeneratedExtension<MessageType, Type> extension, final Type value) {
+      return setExtension((ExtensionLite<MessageType, Type>) extension, value);
+    }
+    /** Set the value of one element of a repeated extension. */
+    public final <Type> BuilderType setExtension(
+        final Extension<MessageType, List<Type>> extension, final int index, final Type value) {
+      return setExtension((ExtensionLite<MessageType, List<Type>>) extension, index, value);
+    }
+    /** Set the value of one element of a repeated extension. */
+    public <Type> BuilderType setExtension(
+        final GeneratedExtension<MessageType, List<Type>> extension,
+        final int index,
+        final Type value) {
+      return setExtension((ExtensionLite<MessageType, List<Type>>) extension, index, value);
+    }
+    /** Append a value to a repeated extension. */
+    public final <Type> BuilderType addExtension(
+        final Extension<MessageType, List<Type>> extension, final Type value) {
+      return addExtension((ExtensionLite<MessageType, List<Type>>) extension, value);
+    }
+    /** Append a value to a repeated extension. */
+    public <Type> BuilderType addExtension(
+        final GeneratedExtension<MessageType, List<Type>> extension, final Type value) {
+      return addExtension((ExtensionLite<MessageType, List<Type>>) extension, value);
+    }
+    /** Clear an extension. */
+    public final <Type> BuilderType clearExtension(final Extension<MessageType, ?> extension) {
+      return clearExtension((ExtensionLite<MessageType, ?>) extension);
+    }
+    /** Clear an extension. */
+    public <Type> BuilderType clearExtension(final GeneratedExtension<MessageType, ?> extension) {
+      return clearExtension((ExtensionLite<MessageType, ?>) extension);
+    }
+
+    /** Called by subclasses to check if all extensions are initialized. */
+    protected boolean extensionsAreInitialized() {
+      return extensions.isInitialized();
+    }
+
+    /**
+     * Called by the build code path to create a copy of the extensions for building the message.
+     */
+    private FieldSet<FieldDescriptor> buildExtensions() {
+      extensions.makeImmutable();
+      return extensions;
+    }
+
+    @Override
+    public boolean isInitialized() {
+      return super.isInitialized() && extensionsAreInitialized();
+    }
+
+    /**
+     * Called by subclasses to parse an unknown field or an extension.
+     *
+     * @return {@code true} unless the tag is an end-group tag.
+     */
+    @Override
+    protected boolean parseUnknownField(
+        final CodedInputStream input,
+        final UnknownFieldSet.Builder unknownFields,
+        final ExtensionRegistryLite extensionRegistry,
+        final int tag)
+        throws IOException {
+      return MessageReflection.mergeFieldFrom(
+          input,
+          unknownFields,
+          extensionRegistry,
+          getDescriptorForType(),
+          new MessageReflection.BuilderAdapter(this),
+          tag);
+    }
+
+    // ---------------------------------------------------------------
+    // Reflection
+
+    @Override
+    public Map<FieldDescriptor, Object> getAllFields() {
+      final Map<FieldDescriptor, Object> result = super.getAllFieldsMutable();
+      result.putAll(extensions.getAllFields());
+      return Collections.unmodifiableMap(result);
+    }
+
+    @Override
+    public Object getField(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        final Object value = extensions.getField(field);
+        if (value == null) {
+          if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+            // Lacking an ExtensionRegistry, we have no way to determine the
+            // extension's real type, so we return a DynamicMessage.
+            return DynamicMessage.getDefaultInstance(field.getMessageType());
+          } else {
+            return field.getDefaultValue();
+          }
+        } else {
+          return value;
+        }
+      } else {
+        return super.getField(field);
+      }
+    }
+
+    @Override
+    public int getRepeatedFieldCount(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        return extensions.getRepeatedFieldCount(field);
+      } else {
+        return super.getRepeatedFieldCount(field);
+      }
+    }
+
+    @Override
+    public Object getRepeatedField(final FieldDescriptor field, final int index) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        return extensions.getRepeatedField(field, index);
+      } else {
+        return super.getRepeatedField(field, index);
+      }
+    }
+
+    @Override
+    public boolean hasField(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        return extensions.hasField(field);
+      } else {
+        return super.hasField(field);
+      }
+    }
+
+    @Override
+    public BuilderType setField(final FieldDescriptor field, final Object value) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        ensureExtensionsIsMutable();
+        extensions.setField(field, value);
+        onChanged();
+        return (BuilderType) this;
+      } else {
+        return super.setField(field, value);
+      }
+    }
+
+    @Override
+    public BuilderType clearField(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        ensureExtensionsIsMutable();
+        extensions.clearField(field);
+        onChanged();
+        return (BuilderType) this;
+      } else {
+        return super.clearField(field);
+      }
+    }
+
+    @Override
+    public BuilderType setRepeatedField(
+        final FieldDescriptor field, final int index, final Object value) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        ensureExtensionsIsMutable();
+        extensions.setRepeatedField(field, index, value);
+        onChanged();
+        return (BuilderType) this;
+      } else {
+        return super.setRepeatedField(field, index, value);
+      }
+    }
+
+    @Override
+    public BuilderType addRepeatedField(final FieldDescriptor field, final Object value) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        ensureExtensionsIsMutable();
+        extensions.addRepeatedField(field, value);
+        onChanged();
+        return (BuilderType) this;
+      } else {
+        return super.addRepeatedField(field, value);
+      }
+    }
+
+    protected final void mergeExtensionFields(final ExtendableMessage other) {
+      ensureExtensionsIsMutable();
+      extensions.mergeFrom(other.extensions);
+      onChanged();
+    }
+
+    private void verifyContainingType(final FieldDescriptor field) {
+      if (field.getContainingType() != getDescriptorForType()) {
+        throw new IllegalArgumentException("FieldDescriptor does not match message type.");
+      }
+    }
+  }
+
+  // -----------------------------------------------------------------
+
+  /**
+   * Gets the descriptor for an extension. The implementation depends on whether the extension is
+   * scoped in the top level of a file or scoped in a Message.
+   */
+  static interface ExtensionDescriptorRetriever {
+    FieldDescriptor getDescriptor();
+  }
+
+  /** For use by generated code only. */
+  public static <ContainingType extends Message, Type>
+      GeneratedExtension<ContainingType, Type> newMessageScopedGeneratedExtension(
+          final Message scope,
+          final int descriptorIndex,
+          final Class singularType,
+          final Message defaultInstance) {
+    // For extensions scoped within a Message, we use the Message to resolve
+    // the outer class's descriptor, from which the extension descriptor is
+    // obtained.
+    return new GeneratedExtension<ContainingType, Type>(
+        new CachedDescriptorRetriever() {
+          @Override
+          public FieldDescriptor loadDescriptor() {
+            return scope.getDescriptorForType().getExtensions().get(descriptorIndex);
+          }
+        },
+        singularType,
+        defaultInstance,
+        Extension.ExtensionType.IMMUTABLE);
+  }
+
+  /** For use by generated code only. */
+  public static <ContainingType extends Message, Type>
+      GeneratedExtension<ContainingType, Type> newFileScopedGeneratedExtension(
+          final Class singularType, final Message defaultInstance) {
+    // For extensions scoped within a file, we rely on the outer class's
+    // static initializer to call internalInit() on the extension when the
+    // descriptor is available.
+    return new GeneratedExtension<ContainingType, Type>(
+        null, // ExtensionDescriptorRetriever is initialized in internalInit();
+        singularType,
+        defaultInstance,
+        Extension.ExtensionType.IMMUTABLE);
+  }
+
+  private abstract static class CachedDescriptorRetriever implements ExtensionDescriptorRetriever {
+    private volatile FieldDescriptor descriptor;
+
+    protected abstract FieldDescriptor loadDescriptor();
+
+    @Override
+    public FieldDescriptor getDescriptor() {
+      if (descriptor == null) {
+        synchronized (this) {
+          if (descriptor == null) {
+            descriptor = loadDescriptor();
+          }
+        }
+      }
+      return descriptor;
+    }
+  }
+
+  /**
+   * Used in proto1 generated code only.
+   *
+   * <p>After enabling bridge, we can define proto2 extensions (the extended type is a proto2
+   * mutable message) in a proto1 .proto file. For these extensions we should generate proto2
+   * GeneratedExtensions.
+   */
+  public static <ContainingType extends Message, Type>
+      GeneratedExtension<ContainingType, Type> newMessageScopedGeneratedExtension(
+          final Message scope,
+          final String name,
+          final Class singularType,
+          final Message defaultInstance) {
+    // For extensions scoped within a Message, we use the Message to resolve
+    // the outer class's descriptor, from which the extension descriptor is
+    // obtained.
+    return new GeneratedExtension<ContainingType, Type>(
+        new CachedDescriptorRetriever() {
+          @Override
+          protected FieldDescriptor loadDescriptor() {
+            return scope.getDescriptorForType().findFieldByName(name);
+          }
+        },
+        singularType,
+        defaultInstance,
+        Extension.ExtensionType.MUTABLE);
+  }
+
+  /**
+   * Used in proto1 generated code only.
+   *
+   * <p>After enabling bridge, we can define proto2 extensions (the extended type is a proto2
+   * mutable message) in a proto1 .proto file. For these extensions we should generate proto2
+   * GeneratedExtensions.
+   */
+  public static <ContainingType extends Message, Type>
+      GeneratedExtension<ContainingType, Type> newFileScopedGeneratedExtension(
+          final Class singularType,
+          final Message defaultInstance,
+          final String descriptorOuterClass,
+          final String extensionName) {
+    // For extensions scoped within a file, we load the descriptor outer
+    // class and rely on it to get the FileDescriptor which then can be
+    // used to obtain the extension's FieldDescriptor.
+    return new GeneratedExtension<ContainingType, Type>(
+        new CachedDescriptorRetriever() {
+          @Override
+          protected FieldDescriptor loadDescriptor() {
+            try {
+              Class clazz = singularType.getClassLoader().loadClass(descriptorOuterClass);
+              FileDescriptor file = (FileDescriptor) clazz.getField("descriptor").get(null);
+              return file.findExtensionByName(extensionName);
+            } catch (Exception e) {
+              throw new RuntimeException(
+                  "Cannot load descriptors: "
+                      + descriptorOuterClass
+                      + " is not a valid descriptor class name",
+                  e);
+            }
+          }
+        },
+        singularType,
+        defaultInstance,
+        Extension.ExtensionType.MUTABLE);
+  }
+
+  /**
+   * Type used to represent generated extensions. The protocol compiler generates a static singleton
+   * instance of this class for each extension.
+   *
+   * <p>For example, imagine you have the {@code .proto} file:
+   *
+   * <pre>
+   * option java_class = "MyProto";
+   *
+   * message Foo {
+   *   extensions 1000 to max;
+   * }
+   *
+   * extend Foo {
+   *   optional int32 bar;
+   * }
+   * </pre>
+   *
+   * <p>Then, {@code MyProto.Foo.bar} has type {@code GeneratedExtension<MyProto.Foo, Integer>}.
+   *
+   * <p>In general, users should ignore the details of this type, and simply use these static
+   * singletons as parameters to the extension accessors defined in {@link ExtendableMessage} and
+   * {@link ExtendableBuilder}.
+   */
+  public static class GeneratedExtension<ContainingType extends Message, Type>
+      extends Extension<ContainingType, Type> {
+    // TODO:  Find ways to avoid using Java reflection within this
+    //   class.  Also try to avoid suppressing unchecked warnings.
+
+    // We can't always initialize the descriptor of a GeneratedExtension when
+    // we first construct it due to initialization order difficulties (namely,
+    // the descriptor may not have been constructed yet, since it is often
+    // constructed by the initializer of a separate module).
+    //
+    // In the case of nested extensions, we initialize the
+    // ExtensionDescriptorRetriever with an instance that uses the scoping
+    // Message's default instance to retrieve the extension's descriptor.
+    //
+    // In the case of non-nested extensions, we initialize the
+    // ExtensionDescriptorRetriever to null and rely on the outer class's static
+    // initializer to call internalInit() after the descriptor has been parsed.
+    GeneratedExtension(
+        ExtensionDescriptorRetriever descriptorRetriever,
+        Class singularType,
+        Message messageDefaultInstance,
+        ExtensionType extensionType) {
+      if (Message.class.isAssignableFrom(singularType)
+          && !singularType.isInstance(messageDefaultInstance)) {
+        throw new IllegalArgumentException(
+            "Bad messageDefaultInstance for " + singularType.getName());
+      }
+      this.descriptorRetriever = descriptorRetriever;
+      this.singularType = singularType;
+      this.messageDefaultInstance = messageDefaultInstance;
+
+      if (ProtocolMessageEnum.class.isAssignableFrom(singularType)) {
+        this.enumValueOf = getMethodOrDie(singularType, "valueOf", EnumValueDescriptor.class);
+        this.enumGetValueDescriptor = getMethodOrDie(singularType, "getValueDescriptor");
+      } else {
+        this.enumValueOf = null;
+        this.enumGetValueDescriptor = null;
+      }
+      this.extensionType = extensionType;
+    }
+
+    /** For use by generated code only. */
+    public void internalInit(final FieldDescriptor descriptor) {
+      if (descriptorRetriever != null) {
+        throw new IllegalStateException("Already initialized.");
+      }
+      descriptorRetriever =
+          new ExtensionDescriptorRetriever() {
+            @Override
+            public FieldDescriptor getDescriptor() {
+              return descriptor;
+            }
+          };
+    }
+
+    private ExtensionDescriptorRetriever descriptorRetriever;
+    private final Class singularType;
+    private final Message messageDefaultInstance;
+    private final Method enumValueOf;
+    private final Method enumGetValueDescriptor;
+    private final ExtensionType extensionType;
+
+    @Override
+    public FieldDescriptor getDescriptor() {
+      if (descriptorRetriever == null) {
+        throw new IllegalStateException("getDescriptor() called before internalInit()");
+      }
+      return descriptorRetriever.getDescriptor();
+    }
+
+    /**
+     * If the extension is an embedded message or group, returns the default instance of the
+     * message.
+     */
+    @Override
+    public Message getMessageDefaultInstance() {
+      return messageDefaultInstance;
+    }
+
+    @Override
+    protected ExtensionType getExtensionType() {
+      return extensionType;
+    }
+
+    /**
+     * Convert from the type used by the reflection accessors to the type used by native accessors.
+     * E.g., for enums, the reflection accessors use EnumValueDescriptors but the native accessors
+     * use the generated enum type.
+     */
+    @Override
+    @SuppressWarnings("unchecked")
+    protected Object fromReflectionType(final Object value) {
+      FieldDescriptor descriptor = getDescriptor();
+      if (descriptor.isRepeated()) {
+        if (descriptor.getJavaType() == FieldDescriptor.JavaType.MESSAGE
+            || descriptor.getJavaType() == FieldDescriptor.JavaType.ENUM) {
+          // Must convert the whole list.
+          final List result = new ArrayList();
+          for (final Object element : (List) value) {
+            result.add(singularFromReflectionType(element));
+          }
+          return result;
+        } else {
+          return value;
+        }
+      } else {
+        return singularFromReflectionType(value);
+      }
+    }
+
+    /**
+     * Like {@link #fromReflectionType(Object)}, but if the type is a repeated type, this converts a
+     * single element.
+     */
+    @Override
+    protected Object singularFromReflectionType(final Object value) {
+      FieldDescriptor descriptor = getDescriptor();
+      switch (descriptor.getJavaType()) {
+        case MESSAGE:
+          if (singularType.isInstance(value)) {
+            return value;
+          } else {
+            return messageDefaultInstance.newBuilderForType().mergeFrom((Message) value).build();
+          }
+        case ENUM:
+          return invokeOrDie(enumValueOf, null, (EnumValueDescriptor) value);
+        default:
+          return value;
+      }
+    }
+
+    /**
+     * Convert from the type used by the native accessors to the type used by reflection accessors.
+     * E.g., for enums, the reflection accessors use EnumValueDescriptors but the native accessors
+     * use the generated enum type.
+     */
+    @Override
+    @SuppressWarnings("unchecked")
+    protected Object toReflectionType(final Object value) {
+      FieldDescriptor descriptor = getDescriptor();
+      if (descriptor.isRepeated()) {
+        if (descriptor.getJavaType() == FieldDescriptor.JavaType.ENUM) {
+          // Must convert the whole list.
+          final List result = new ArrayList();
+          for (final Object element : (List) value) {
+            result.add(singularToReflectionType(element));
+          }
+          return result;
+        } else {
+          return value;
+        }
+      } else {
+        return singularToReflectionType(value);
+      }
+    }
+
+    /**
+     * Like {@link #toReflectionType(Object)}, but if the type is a repeated type, this converts a
+     * single element.
+     */
+    @Override
+    protected Object singularToReflectionType(final Object value) {
+      FieldDescriptor descriptor = getDescriptor();
+      switch (descriptor.getJavaType()) {
+        case ENUM:
+          return invokeOrDie(enumGetValueDescriptor, value);
+        default:
+          return value;
+      }
+    }
+
+    @Override
+    public int getNumber() {
+      return getDescriptor().getNumber();
+    }
+
+    @Override
+    public WireFormat.FieldType getLiteType() {
+      return getDescriptor().getLiteType();
+    }
+
+    @Override
+    public boolean isRepeated() {
+      return getDescriptor().isRepeated();
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public Type getDefaultValue() {
+      if (isRepeated()) {
+        return (Type) Collections.emptyList();
+      }
+      if (getDescriptor().getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+        return (Type) messageDefaultInstance;
+      }
+      return (Type) singularFromReflectionType(getDescriptor().getDefaultValue());
+    }
+  }
+
+  // =================================================================
+
+  /** Calls Class.getMethod and throws a RuntimeException if it fails. */
+  @SuppressWarnings("unchecked")
+  private static Method getMethodOrDie(
+      final Class clazz, final String name, final Class... params) {
+    try {
+      return clazz.getMethod(name, params);
+    } catch (NoSuchMethodException e) {
+      throw new RuntimeException(
+          "Generated message class \"" + clazz.getName() + "\" missing method \"" + name + "\".",
+          e);
+    }
+  }
+
+  /** Calls invoke and throws a RuntimeException if it fails. */
+  private static Object invokeOrDie(
+      final Method method, final Object object, final Object... params) {
+    try {
+      return method.invoke(object, params);
+    } catch (IllegalAccessException e) {
+      throw new RuntimeException(
+          "Couldn't use Java reflection to implement protocol message " + "reflection.", e);
+    } catch (InvocationTargetException e) {
+      final Throwable cause = e.getCause();
+      if (cause instanceof RuntimeException) {
+        throw (RuntimeException) cause;
+      } else if (cause instanceof Error) {
+        throw (Error) cause;
+      } else {
+        throw new RuntimeException(
+            "Unexpected exception thrown by generated accessor method.", cause);
+      }
+    }
+  }
+
+  /**
+   * Gets the map field with the given field number. This method should be overridden in the
+   * generated message class if the message contains map fields.
+   *
+   * <p>Unlike other field types, reflection support for map fields can't be implemented based on
+   * generated public API because we need to access a map field as a list in reflection API but the
+   * generated API only allows us to access it as a map. This method returns the underlying map
+   * field directly and thus enables us to access the map field as a list.
+   */
+  @SuppressWarnings({"rawtypes", "unused"})
+  protected MapField internalGetMapField(int fieldNumber) {
+    // Note that we can't use descriptor names here because this method will
+    // be called when descriptor is being initialized.
+    throw new RuntimeException("No map fields found in " + getClass().getName());
+  }
+
+  /**
+   * Users should ignore this class. This class provides the implementation with access to the
+   * fields of a message object using Java reflection.
+   */
+  public static final class FieldAccessorTable {
+
+    /**
+     * Construct a FieldAccessorTable for a particular message class. Only one FieldAccessorTable
+     * should ever be constructed per class.
+     *
+     * @param descriptor The type's descriptor.
+     * @param camelCaseNames The camelcase names of all fields in the message. These are used to
+     *     derive the accessor method names.
+     * @param messageClass The message type.
+     * @param builderClass The builder type.
+     */
+    public FieldAccessorTable(
+        final Descriptor descriptor,
+        final String[] camelCaseNames,
+        final Class<? extends GeneratedMessageInternal> messageClass,
+        final Class<? extends Builder> builderClass) {
+      this(descriptor, camelCaseNames);
+      ensureFieldAccessorsInitialized(messageClass, builderClass);
+    }
+
+    /**
+     * Construct a FieldAccessorTable for a particular message class without initializing
+     * FieldAccessors.
+     */
+    public FieldAccessorTable(final Descriptor descriptor, final String[] camelCaseNames) {
+      this.descriptor = descriptor;
+      this.camelCaseNames = camelCaseNames;
+      fields = new FieldAccessor[descriptor.getFields().size()];
+      oneofs = new OneofAccessor[descriptor.getOneofs().size()];
+      initialized = false;
+    }
+
+    private boolean isMapFieldEnabled(FieldDescriptor field) {
+      boolean result = true;
+      return result;
+    }
+
+    /**
+     * Ensures the field accessors are initialized. This method is thread-safe.
+     *
+     * @param messageClass The message type.
+     * @param builderClass The builder type.
+     * @return this
+     */
+    public FieldAccessorTable ensureFieldAccessorsInitialized(
+        Class<? extends GeneratedMessageInternal> messageClass, Class<? extends Builder> builderClass) {
+      if (initialized) {
+        return this;
+      }
+      synchronized (this) {
+        if (initialized) {
+          return this;
+        }
+        int fieldsSize = fields.length;
+        for (int i = 0; i < fieldsSize; i++) {
+          FieldDescriptor field = descriptor.getFields().get(i);
+          String containingOneofCamelCaseName = null;
+          if (field.getContainingOneof() != null) {
+            containingOneofCamelCaseName =
+                camelCaseNames[fieldsSize + field.getContainingOneof().getIndex()];
+          }
+          if (field.isRepeated()) {
+            if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+              if (field.isMapField() && isMapFieldEnabled(field)) {
+                fields[i] =
+                    new MapFieldAccessor(field, camelCaseNames[i], messageClass, builderClass);
+              } else {
+                fields[i] =
+                    new RepeatedMessageFieldAccessor(
+                        field, camelCaseNames[i], messageClass, builderClass);
+              }
+            } else if (field.getJavaType() == FieldDescriptor.JavaType.ENUM) {
+              fields[i] =
+                  new RepeatedEnumFieldAccessor(
+                      field, camelCaseNames[i], messageClass, builderClass);
+            } else {
+              fields[i] =
+                  new RepeatedFieldAccessor(field, camelCaseNames[i], messageClass, builderClass);
+            }
+          } else {
+            if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+              fields[i] =
+                  new SingularMessageFieldAccessor(
+                      field,
+                      camelCaseNames[i],
+                      messageClass,
+                      builderClass,
+                      containingOneofCamelCaseName);
+            } else if (field.getJavaType() == FieldDescriptor.JavaType.ENUM) {
+              fields[i] =
+                  new SingularEnumFieldAccessor(
+                      field,
+                      camelCaseNames[i],
+                      messageClass,
+                      builderClass,
+                      containingOneofCamelCaseName);
+            } else if (field.getJavaType() == FieldDescriptor.JavaType.STRING) {
+              fields[i] =
+                  new SingularStringFieldAccessor(
+                      field,
+                      camelCaseNames[i],
+                      messageClass,
+                      builderClass,
+                      containingOneofCamelCaseName);
+            } else {
+              fields[i] =
+                  new SingularFieldAccessor(
+                      field,
+                      camelCaseNames[i],
+                      messageClass,
+                      builderClass,
+                      containingOneofCamelCaseName);
+            }
+          }
+        }
+
+        int oneofsSize = oneofs.length;
+        for (int i = 0; i < oneofsSize; i++) {
+          oneofs[i] =
+              new OneofAccessor(
+                  descriptor, camelCaseNames[i + fieldsSize], messageClass, builderClass);
+        }
+        initialized = true;
+        camelCaseNames = null;
+        return this;
+      }
+    }
+
+    private final Descriptor descriptor;
+    private final FieldAccessor[] fields;
+    private String[] camelCaseNames;
+    private final OneofAccessor[] oneofs;
+    private volatile boolean initialized;
+
+    /** Get the FieldAccessor for a particular field. */
+    private FieldAccessor getField(final FieldDescriptor field) {
+      if (field.getContainingType() != descriptor) {
+        throw new IllegalArgumentException("FieldDescriptor does not match message type.");
+      } else if (field.isExtension()) {
+        // If this type had extensions, it would subclass ExtendableMessage,
+        // which overrides the reflection interface to handle extensions.
+        throw new IllegalArgumentException("This type does not have extensions.");
+      }
+      return fields[field.getIndex()];
+    }
+
+    /** Get the OneofAccessor for a particular oneof. */
+    private OneofAccessor getOneof(final OneofDescriptor oneof) {
+      if (oneof.getContainingType() != descriptor) {
+        throw new IllegalArgumentException("OneofDescriptor does not match message type.");
+      }
+      return oneofs[oneof.getIndex()];
+    }
+
+    /**
+     * Abstract interface that provides access to a single field. This is implemented differently
+     * depending on the field type and cardinality.
+     */
+    private interface FieldAccessor {
+      Object get(GeneratedMessageInternal message);
+
+      Object get(GeneratedMessageInternal.Builder builder);
+
+      Object getRaw(GeneratedMessageInternal message);
+
+      Object getRaw(GeneratedMessageInternal.Builder builder);
+
+      void set(Builder builder, Object value);
+
+      Object getRepeated(GeneratedMessageInternal message, int index);
+
+      Object getRepeated(GeneratedMessageInternal.Builder builder, int index);
+
+      Object getRepeatedRaw(GeneratedMessageInternal message, int index);
+
+      Object getRepeatedRaw(GeneratedMessageInternal.Builder builder, int index);
+
+      void setRepeated(Builder builder, int index, Object value);
+
+      void addRepeated(Builder builder, Object value);
+
+      boolean has(GeneratedMessageInternal message);
+
+      boolean has(GeneratedMessageInternal.Builder builder);
+
+      int getRepeatedCount(GeneratedMessageInternal message);
+
+      int getRepeatedCount(GeneratedMessageInternal.Builder builder);
+
+      void clear(Builder builder);
+
+      Message.Builder newBuilder();
+
+      Message.Builder getBuilder(GeneratedMessageInternal.Builder builder);
+
+      Message.Builder getRepeatedBuilder(GeneratedMessageInternal.Builder builder, int index);
+    }
+
+    /** OneofAccessor provides access to a single oneof. */
+    private static class OneofAccessor {
+      OneofAccessor(
+          final Descriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends GeneratedMessageInternal> messageClass,
+          final Class<? extends Builder> builderClass) {
+        this.descriptor = descriptor;
+        caseMethod = getMethodOrDie(messageClass, "get" + camelCaseName + "Case");
+        caseMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName + "Case");
+        clearMethod = getMethodOrDie(builderClass, "clear" + camelCaseName);
+      }
+
+      private final Descriptor descriptor;
+      private final Method caseMethod;
+      private final Method caseMethodBuilder;
+      private final Method clearMethod;
+
+      public boolean has(final GeneratedMessageInternal message) {
+        if (((Internal.EnumLite) invokeOrDie(caseMethod, message)).getNumber() == 0) {
+          return false;
+        }
+        return true;
+      }
+
+      public boolean has(GeneratedMessageInternal.Builder builder) {
+        if (((Internal.EnumLite) invokeOrDie(caseMethodBuilder, builder)).getNumber() == 0) {
+          return false;
+        }
+        return true;
+      }
+
+      public FieldDescriptor get(final GeneratedMessageInternal message) {
+        int fieldNumber = ((Internal.EnumLite) invokeOrDie(caseMethod, message)).getNumber();
+        if (fieldNumber > 0) {
+          return descriptor.findFieldByNumber(fieldNumber);
+        }
+        return null;
+      }
+
+      public FieldDescriptor get(GeneratedMessageInternal.Builder builder) {
+        int fieldNumber = ((Internal.EnumLite) invokeOrDie(caseMethodBuilder, builder)).getNumber();
+        if (fieldNumber > 0) {
+          return descriptor.findFieldByNumber(fieldNumber);
+        }
+        return null;
+      }
+
+      public void clear(final Builder builder) {
+        invokeOrDie(clearMethod, builder);
+      }
+    }
+
+    private static boolean supportFieldPresence(FileDescriptor file) {
+      return file.getSyntax() == FileDescriptor.Syntax.PROTO2;
+    }
+
+    // ---------------------------------------------------------------
+
+    private static class SingularFieldAccessor implements FieldAccessor {
+      SingularFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends GeneratedMessageInternal> messageClass,
+          final Class<? extends Builder> builderClass,
+          final String containingOneofCamelCaseName) {
+        field = descriptor;
+        isOneofField = descriptor.getContainingOneof() != null;
+        hasHasMethod =
+            supportFieldPresence(descriptor.getFile())
+                || (!isOneofField && descriptor.getJavaType() == FieldDescriptor.JavaType.MESSAGE);
+        getMethod = getMethodOrDie(messageClass, "get" + camelCaseName);
+        getMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName);
+        type = getMethod.getReturnType();
+        setMethod = getMethodOrDie(builderClass, "set" + camelCaseName, type);
+        hasMethod = hasHasMethod ? getMethodOrDie(messageClass, "has" + camelCaseName) : null;
+        hasMethodBuilder =
+            hasHasMethod ? getMethodOrDie(builderClass, "has" + camelCaseName) : null;
+        clearMethod = getMethodOrDie(builderClass, "clear" + camelCaseName);
+        caseMethod =
+            isOneofField
+                ? getMethodOrDie(messageClass, "get" + containingOneofCamelCaseName + "Case")
+                : null;
+        caseMethodBuilder =
+            isOneofField
+                ? getMethodOrDie(builderClass, "get" + containingOneofCamelCaseName + "Case")
+                : null;
+      }
+
+      // Note:  We use Java reflection to call public methods rather than
+      //   access private fields directly as this avoids runtime security
+      //   checks.
+      protected final Class<?> type;
+      protected final Method getMethod;
+      protected final Method getMethodBuilder;
+      protected final Method setMethod;
+      protected final Method hasMethod;
+      protected final Method hasMethodBuilder;
+      protected final Method clearMethod;
+      protected final Method caseMethod;
+      protected final Method caseMethodBuilder;
+      protected final FieldDescriptor field;
+      protected final boolean isOneofField;
+      protected final boolean hasHasMethod;
+
+      private int getOneofFieldNumber(final GeneratedMessageInternal message) {
+        return ((Internal.EnumLite) invokeOrDie(caseMethod, message)).getNumber();
+      }
+
+      private int getOneofFieldNumber(final GeneratedMessageInternal.Builder builder) {
+        return ((Internal.EnumLite) invokeOrDie(caseMethodBuilder, builder)).getNumber();
+      }
+
+      @Override
+      public Object get(final GeneratedMessageInternal message) {
+        return invokeOrDie(getMethod, message);
+      }
+
+      @Override
+      public Object get(GeneratedMessageInternal.Builder builder) {
+        return invokeOrDie(getMethodBuilder, builder);
+      }
+
+      @Override
+      public Object getRaw(final GeneratedMessageInternal message) {
+        return get(message);
+      }
+
+      @Override
+      public Object getRaw(GeneratedMessageInternal.Builder builder) {
+        return get(builder);
+      }
+
+      @Override
+      public void set(final Builder builder, final Object value) {
+        invokeOrDie(setMethod, builder, value);
+      }
+
+      @Override
+      public Object getRepeated(final GeneratedMessageInternal message, final int index) {
+        throw new UnsupportedOperationException("getRepeatedField() called on a singular field.");
+      }
+
+      @Override
+      public Object getRepeatedRaw(final GeneratedMessageInternal message, final int index) {
+        throw new UnsupportedOperationException(
+            "getRepeatedFieldRaw() called on a singular field.");
+      }
+
+      @Override
+      public Object getRepeated(GeneratedMessageInternal.Builder builder, int index) {
+        throw new UnsupportedOperationException("getRepeatedField() called on a singular field.");
+      }
+
+      @Override
+      public Object getRepeatedRaw(GeneratedMessageInternal.Builder builder, int index) {
+        throw new UnsupportedOperationException(
+            "getRepeatedFieldRaw() called on a singular field.");
+      }
+
+      @Override
+      public void setRepeated(final Builder builder, final int index, final Object value) {
+        throw new UnsupportedOperationException("setRepeatedField() called on a singular field.");
+      }
+
+      @Override
+      public void addRepeated(final Builder builder, final Object value) {
+        throw new UnsupportedOperationException("addRepeatedField() called on a singular field.");
+      }
+
+      @Override
+      public boolean has(final GeneratedMessageInternal message) {
+        if (!hasHasMethod) {
+          if (isOneofField) {
+            return getOneofFieldNumber(message) == field.getNumber();
+          }
+          return !get(message).equals(field.getDefaultValue());
+        }
+        return (Boolean) invokeOrDie(hasMethod, message);
+      }
+
+      @Override
+      public boolean has(GeneratedMessageInternal.Builder builder) {
+        if (!hasHasMethod) {
+          if (isOneofField) {
+            return getOneofFieldNumber(builder) == field.getNumber();
+          }
+          return !get(builder).equals(field.getDefaultValue());
+        }
+        return (Boolean) invokeOrDie(hasMethodBuilder, builder);
+      }
+
+      @Override
+      public int getRepeatedCount(final GeneratedMessageInternal message) {
+        throw new UnsupportedOperationException(
+            "getRepeatedFieldSize() called on a singular field.");
+      }
+
+      @Override
+      public int getRepeatedCount(GeneratedMessageInternal.Builder builder) {
+        throw new UnsupportedOperationException(
+            "getRepeatedFieldSize() called on a singular field.");
+      }
+
+      @Override
+      public void clear(final Builder builder) {
+        invokeOrDie(clearMethod, builder);
+      }
+
+      @Override
+      public Message.Builder newBuilder() {
+        throw new UnsupportedOperationException(
+            "newBuilderForField() called on a non-Message type.");
+      }
+
+      @Override
+      public Message.Builder getBuilder(GeneratedMessageInternal.Builder builder) {
+        throw new UnsupportedOperationException("getFieldBuilder() called on a non-Message type.");
+      }
+
+      @Override
+      public Message.Builder getRepeatedBuilder(GeneratedMessageInternal.Builder builder, int index) {
+        throw new UnsupportedOperationException(
+            "getRepeatedFieldBuilder() called on a non-Message type.");
+      }
+    }
+
+    private static class RepeatedFieldAccessor implements FieldAccessor {
+      protected final Class type;
+      protected final Method getMethod;
+      protected final Method getMethodBuilder;
+      protected final Method getRepeatedMethod;
+      protected final Method getRepeatedMethodBuilder;
+      protected final Method setRepeatedMethod;
+      protected final Method addRepeatedMethod;
+      protected final Method getCountMethod;
+      protected final Method getCountMethodBuilder;
+      protected final Method clearMethod;
+
+      RepeatedFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends GeneratedMessageInternal> messageClass,
+          final Class<? extends Builder> builderClass) {
+        getMethod = getMethodOrDie(messageClass, "get" + camelCaseName + "List");
+        getMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName + "List");
+        getRepeatedMethod = getMethodOrDie(messageClass, "get" + camelCaseName, Integer.TYPE);
+        getRepeatedMethodBuilder =
+            getMethodOrDie(builderClass, "get" + camelCaseName, Integer.TYPE);
+        type = getRepeatedMethod.getReturnType();
+        setRepeatedMethod = getMethodOrDie(builderClass, "set" + camelCaseName, Integer.TYPE, type);
+        addRepeatedMethod = getMethodOrDie(builderClass, "add" + camelCaseName, type);
+        getCountMethod = getMethodOrDie(messageClass, "get" + camelCaseName + "Count");
+        getCountMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName + "Count");
+
+        clearMethod = getMethodOrDie(builderClass, "clear" + camelCaseName);
+      }
+
+      @Override
+      public Object get(final GeneratedMessageInternal message) {
+        return invokeOrDie(getMethod, message);
+      }
+
+      @Override
+      public Object get(GeneratedMessageInternal.Builder builder) {
+        return invokeOrDie(getMethodBuilder, builder);
+      }
+
+      @Override
+      public Object getRaw(final GeneratedMessageInternal message) {
+        return get(message);
+      }
+
+      @Override
+      public Object getRaw(GeneratedMessageInternal.Builder builder) {
+        return get(builder);
+      }
+
+      @Override
+      public void set(final Builder builder, final Object value) {
+        // Add all the elements individually.  This serves two purposes:
+        // 1) Verifies that each element has the correct type.
+        // 2) Insures that the caller cannot modify the list later on and
+        //    have the modifications be reflected in the message.
+        clear(builder);
+        for (final Object element : (List<?>) value) {
+          addRepeated(builder, element);
+        }
+      }
+
+      @Override
+      public Object getRepeated(final GeneratedMessageInternal message, final int index) {
+        return invokeOrDie(getRepeatedMethod, message, index);
+      }
+
+      @Override
+      public Object getRepeated(GeneratedMessageInternal.Builder builder, int index) {
+        return invokeOrDie(getRepeatedMethodBuilder, builder, index);
+      }
+
+      @Override
+      public Object getRepeatedRaw(GeneratedMessageInternal message, int index) {
+        return getRepeated(message, index);
+      }
+
+      @Override
+      public Object getRepeatedRaw(GeneratedMessageInternal.Builder builder, int index) {
+        return getRepeated(builder, index);
+      }
+
+      @Override
+      public void setRepeated(final Builder builder, final int index, final Object value) {
+        invokeOrDie(setRepeatedMethod, builder, index, value);
+      }
+
+      @Override
+      public void addRepeated(final Builder builder, final Object value) {
+        invokeOrDie(addRepeatedMethod, builder, value);
+      }
+
+      @Override
+      public boolean has(final GeneratedMessageInternal message) {
+        throw new UnsupportedOperationException("hasField() called on a repeated field.");
+      }
+
+      @Override
+      public boolean has(GeneratedMessageInternal.Builder builder) {
+        throw new UnsupportedOperationException("hasField() called on a repeated field.");
+      }
+
+      @Override
+      public int getRepeatedCount(final GeneratedMessageInternal message) {
+        return (Integer) invokeOrDie(getCountMethod, message);
+      }
+
+      @Override
+      public int getRepeatedCount(GeneratedMessageInternal.Builder builder) {
+        return (Integer) invokeOrDie(getCountMethodBuilder, builder);
+      }
+
+      @Override
+      public void clear(final Builder builder) {
+        invokeOrDie(clearMethod, builder);
+      }
+
+      @Override
+      public Message.Builder newBuilder() {
+        throw new UnsupportedOperationException(
+            "newBuilderForField() called on a non-Message type.");
+      }
+
+      @Override
+      public Message.Builder getBuilder(GeneratedMessageInternal.Builder builder) {
+        throw new UnsupportedOperationException("getFieldBuilder() called on a non-Message type.");
+      }
+
+      @Override
+      public Message.Builder getRepeatedBuilder(GeneratedMessageInternal.Builder builder, int index) {
+        throw new UnsupportedOperationException(
+            "getRepeatedFieldBuilder() called on a non-Message type.");
+      }
+    }
+
+    private static class MapFieldAccessor implements FieldAccessor {
+      MapFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends GeneratedMessageInternal> messageClass,
+          final Class<? extends Builder> builderClass) {
+        field = descriptor;
+        Method getDefaultInstanceMethod = getMethodOrDie(messageClass, "getDefaultInstance");
+        MapField defaultMapField =
+            getMapField((GeneratedMessageInternal) invokeOrDie(getDefaultInstanceMethod, null));
+        mapEntryMessageDefaultInstance = defaultMapField.getMapEntryMessageDefaultInstance();
+      }
+
+      private final FieldDescriptor field;
+      private final Message mapEntryMessageDefaultInstance;
+
+      private MapField<?, ?> getMapField(GeneratedMessageInternal message) {
+        return (MapField<?, ?>) message.internalGetMapField(field.getNumber());
+      }
+
+      private MapField<?, ?> getMapField(GeneratedMessageInternal.Builder builder) {
+        return (MapField<?, ?>) builder.internalGetMapField(field.getNumber());
+      }
+
+      private MapField<?, ?> getMutableMapField(GeneratedMessageInternal.Builder builder) {
+        return (MapField<?, ?>) builder.internalGetMutableMapField(field.getNumber());
+      }
+
+      @Override
+      @SuppressWarnings("unchecked")
+      public Object get(GeneratedMessageInternal message) {
+        List result = new ArrayList();
+        for (int i = 0; i < getRepeatedCount(message); i++) {
+          result.add(getRepeated(message, i));
+        }
+        return Collections.unmodifiableList(result);
+      }
+
+      @Override
+      @SuppressWarnings("unchecked")
+      public Object get(Builder builder) {
+        List result = new ArrayList();
+        for (int i = 0; i < getRepeatedCount(builder); i++) {
+          result.add(getRepeated(builder, i));
+        }
+        return Collections.unmodifiableList(result);
+      }
+
+      @Override
+      public Object getRaw(GeneratedMessageInternal message) {
+        return get(message);
+      }
+
+      @Override
+      public Object getRaw(GeneratedMessageInternal.Builder builder) {
+        return get(builder);
+      }
+
+      @Override
+      public void set(Builder builder, Object value) {
+        clear(builder);
+        for (Object entry : (List) value) {
+          addRepeated(builder, entry);
+        }
+      }
+
+      @Override
+      public Object getRepeated(GeneratedMessageInternal message, int index) {
+        return getMapField(message).getList().get(index);
+      }
+
+      @Override
+      public Object getRepeated(Builder builder, int index) {
+        return getMapField(builder).getList().get(index);
+      }
+
+      @Override
+      public Object getRepeatedRaw(GeneratedMessageInternal message, int index) {
+        return getRepeated(message, index);
+      }
+
+      @Override
+      public Object getRepeatedRaw(Builder builder, int index) {
+        return getRepeated(builder, index);
+      }
+
+      @Override
+      public void setRepeated(Builder builder, int index, Object value) {
+        getMutableMapField(builder).getMutableList().set(index, (Message) value);
+      }
+
+      @Override
+      public void addRepeated(Builder builder, Object value) {
+        getMutableMapField(builder).getMutableList().add((Message) value);
+      }
+
+      @Override
+      public boolean has(GeneratedMessageInternal message) {
+        throw new UnsupportedOperationException("hasField() is not supported for repeated fields.");
+      }
+
+      @Override
+      public boolean has(Builder builder) {
+        throw new UnsupportedOperationException("hasField() is not supported for repeated fields.");
+      }
+
+      @Override
+      public int getRepeatedCount(GeneratedMessageInternal message) {
+        return getMapField(message).getList().size();
+      }
+
+      @Override
+      public int getRepeatedCount(Builder builder) {
+        return getMapField(builder).getList().size();
+      }
+
+      @Override
+      public void clear(Builder builder) {
+        getMutableMapField(builder).getMutableList().clear();
+      }
+
+      @Override
+      public Message.Builder newBuilder() {
+        return mapEntryMessageDefaultInstance.newBuilderForType();
+      }
+
+      @Override
+      public Message.Builder getBuilder(Builder builder) {
+        throw new UnsupportedOperationException("Nested builder not supported for map fields.");
+      }
+
+      @Override
+      public Message.Builder getRepeatedBuilder(Builder builder, int index) {
+        throw new UnsupportedOperationException("Nested builder not supported for map fields.");
+      }
+    }
+
+    // ---------------------------------------------------------------
+
+    private static final class SingularEnumFieldAccessor extends SingularFieldAccessor {
+      SingularEnumFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends GeneratedMessageInternal> messageClass,
+          final Class<? extends Builder> builderClass,
+          final String containingOneofCamelCaseName) {
+        super(descriptor, camelCaseName, messageClass, builderClass, containingOneofCamelCaseName);
+
+        enumDescriptor = descriptor.getEnumType();
+
+        valueOfMethod = getMethodOrDie(type, "valueOf", EnumValueDescriptor.class);
+        getValueDescriptorMethod = getMethodOrDie(type, "getValueDescriptor");
+
+        supportUnknownEnumValue = !descriptor.legacyEnumFieldTreatedAsClosed();
+        if (supportUnknownEnumValue) {
+          getValueMethod = getMethodOrDie(messageClass, "get" + camelCaseName + "Value");
+          getValueMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName + "Value");
+          setValueMethod = getMethodOrDie(builderClass, "set" + camelCaseName + "Value", int.class);
+        }
+      }
+
+      private EnumDescriptor enumDescriptor;
+
+      private Method valueOfMethod;
+      private Method getValueDescriptorMethod;
+
+      private boolean supportUnknownEnumValue;
+      private Method getValueMethod;
+      private Method getValueMethodBuilder;
+      private Method setValueMethod;
+
+      @Override
+      public Object get(final GeneratedMessageInternal message) {
+        if (supportUnknownEnumValue) {
+          int value = (Integer) invokeOrDie(getValueMethod, message);
+          return enumDescriptor.findValueByNumberCreatingIfUnknown(value);
+        }
+        return invokeOrDie(getValueDescriptorMethod, super.get(message));
+      }
+
+      @Override
+      public Object get(final GeneratedMessageInternal.Builder builder) {
+        if (supportUnknownEnumValue) {
+          int value = (Integer) invokeOrDie(getValueMethodBuilder, builder);
+          return enumDescriptor.findValueByNumberCreatingIfUnknown(value);
+        }
+        return invokeOrDie(getValueDescriptorMethod, super.get(builder));
+      }
+
+      @Override
+      public void set(final Builder builder, final Object value) {
+        if (supportUnknownEnumValue) {
+          invokeOrDie(setValueMethod, builder, ((EnumValueDescriptor) value).getNumber());
+          return;
+        }
+        super.set(builder, invokeOrDie(valueOfMethod, null, value));
+      }
+    }
+
+    private static final class RepeatedEnumFieldAccessor extends RepeatedFieldAccessor {
+      RepeatedEnumFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends GeneratedMessageInternal> messageClass,
+          final Class<? extends Builder> builderClass) {
+        super(descriptor, camelCaseName, messageClass, builderClass);
+
+        enumDescriptor = descriptor.getEnumType();
+
+        valueOfMethod = getMethodOrDie(type, "valueOf", EnumValueDescriptor.class);
+        getValueDescriptorMethod = getMethodOrDie(type, "getValueDescriptor");
+
+        supportUnknownEnumValue = !descriptor.legacyEnumFieldTreatedAsClosed();
+        if (supportUnknownEnumValue) {
+          getRepeatedValueMethod =
+              getMethodOrDie(messageClass, "get" + camelCaseName + "Value", int.class);
+          getRepeatedValueMethodBuilder =
+              getMethodOrDie(builderClass, "get" + camelCaseName + "Value", int.class);
+          setRepeatedValueMethod =
+              getMethodOrDie(builderClass, "set" + camelCaseName + "Value", int.class, int.class);
+          addRepeatedValueMethod =
+              getMethodOrDie(builderClass, "add" + camelCaseName + "Value", int.class);
+        }
+      }
+
+      private EnumDescriptor enumDescriptor;
+
+      private final Method valueOfMethod;
+      private final Method getValueDescriptorMethod;
+
+      private boolean supportUnknownEnumValue;
+      private Method getRepeatedValueMethod;
+      private Method getRepeatedValueMethodBuilder;
+      private Method setRepeatedValueMethod;
+      private Method addRepeatedValueMethod;
+
+      @Override
+      @SuppressWarnings("unchecked")
+      public Object get(final GeneratedMessageInternal message) {
+        final List newList = new ArrayList();
+        final int size = getRepeatedCount(message);
+        for (int i = 0; i < size; i++) {
+          newList.add(getRepeated(message, i));
+        }
+        return Collections.unmodifiableList(newList);
+      }
+
+      @Override
+      @SuppressWarnings("unchecked")
+      public Object get(final GeneratedMessageInternal.Builder builder) {
+        final List newList = new ArrayList();
+        final int size = getRepeatedCount(builder);
+        for (int i = 0; i < size; i++) {
+          newList.add(getRepeated(builder, i));
+        }
+        return Collections.unmodifiableList(newList);
+      }
+
+      @Override
+      public Object getRepeated(final GeneratedMessageInternal message, final int index) {
+        if (supportUnknownEnumValue) {
+          int value = (Integer) invokeOrDie(getRepeatedValueMethod, message, index);
+          return enumDescriptor.findValueByNumberCreatingIfUnknown(value);
+        }
+        return invokeOrDie(getValueDescriptorMethod, super.getRepeated(message, index));
+      }
+
+      @Override
+      public Object getRepeated(final GeneratedMessageInternal.Builder builder, final int index) {
+        if (supportUnknownEnumValue) {
+          int value = (Integer) invokeOrDie(getRepeatedValueMethodBuilder, builder, index);
+          return enumDescriptor.findValueByNumberCreatingIfUnknown(value);
+        }
+        return invokeOrDie(getValueDescriptorMethod, super.getRepeated(builder, index));
+      }
+
+      @Override
+      public void setRepeated(final Builder builder, final int index, final Object value) {
+        if (supportUnknownEnumValue) {
+          invokeOrDie(
+              setRepeatedValueMethod, builder, index, ((EnumValueDescriptor) value).getNumber());
+          return;
+        }
+        super.setRepeated(builder, index, invokeOrDie(valueOfMethod, null, value));
+      }
+
+      @Override
+      public void addRepeated(final Builder builder, final Object value) {
+        if (supportUnknownEnumValue) {
+          invokeOrDie(addRepeatedValueMethod, builder, ((EnumValueDescriptor) value).getNumber());
+          return;
+        }
+        super.addRepeated(builder, invokeOrDie(valueOfMethod, null, value));
+      }
+    }
+
+    // ---------------------------------------------------------------
+
+    /**
+     * Field accessor for string fields.
+     *
+     * <p>This class makes getFooBytes() and setFooBytes() available for reflection API so that
+     * reflection based serialize/parse functions can access the raw bytes of the field to preserve
+     * non-UTF8 bytes in the string.
+     *
+     * <p>This ensures the serialize/parse round-trip safety, which is important for servers which
+     * forward messages.
+     */
+    private static final class SingularStringFieldAccessor extends SingularFieldAccessor {
+      SingularStringFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends GeneratedMessageInternal> messageClass,
+          final Class<? extends Builder> builderClass,
+          final String containingOneofCamelCaseName) {
+        super(descriptor, camelCaseName, messageClass, builderClass, containingOneofCamelCaseName);
+        getBytesMethod = getMethodOrDie(messageClass, "get" + camelCaseName + "Bytes");
+        getBytesMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName + "Bytes");
+        setBytesMethodBuilder =
+            getMethodOrDie(builderClass, "set" + camelCaseName + "Bytes", ByteString.class);
+      }
+
+      private final Method getBytesMethod;
+      private final Method getBytesMethodBuilder;
+      private final Method setBytesMethodBuilder;
+
+      @Override
+      public Object getRaw(final GeneratedMessageInternal message) {
+        return invokeOrDie(getBytesMethod, message);
+      }
+
+      @Override
+      public Object getRaw(GeneratedMessageInternal.Builder builder) {
+        return invokeOrDie(getBytesMethodBuilder, builder);
+      }
+
+      @Override
+      public void set(GeneratedMessageInternal.Builder builder, Object value) {
+        if (value instanceof ByteString) {
+          invokeOrDie(setBytesMethodBuilder, builder, value);
+        } else {
+          super.set(builder, value);
+        }
+      }
+    }
+
+    // ---------------------------------------------------------------
+
+    private static final class SingularMessageFieldAccessor extends SingularFieldAccessor {
+      SingularMessageFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends GeneratedMessageInternal> messageClass,
+          final Class<? extends Builder> builderClass,
+          final String containingOneofCamelCaseName) {
+        super(descriptor, camelCaseName, messageClass, builderClass, containingOneofCamelCaseName);
+
+        newBuilderMethod = getMethodOrDie(type, "newBuilder");
+        getBuilderMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName + "Builder");
+      }
+
+      private final Method newBuilderMethod;
+      private final Method getBuilderMethodBuilder;
+
+      private Object coerceType(final Object value) {
+        if (type.isInstance(value)) {
+          return value;
+        } else {
+          // The value is not the exact right message type.  However, if it
+          // is an alternative implementation of the same type -- e.g. a
+          // DynamicMessage -- we should accept it.  In this case we can make
+          // a copy of the message.
+          return ((Message.Builder) invokeOrDie(newBuilderMethod, null))
+              .mergeFrom((Message) value)
+              .buildPartial();
+        }
+      }
+
+      @Override
+      public void set(final Builder builder, final Object value) {
+        super.set(builder, coerceType(value));
+      }
+
+      @Override
+      public Message.Builder newBuilder() {
+        return (Message.Builder) invokeOrDie(newBuilderMethod, null);
+      }
+
+      @Override
+      public Message.Builder getBuilder(GeneratedMessageInternal.Builder builder) {
+        return (Message.Builder) invokeOrDie(getBuilderMethodBuilder, builder);
+      }
+    }
+
+    private static final class RepeatedMessageFieldAccessor extends RepeatedFieldAccessor {
+      RepeatedMessageFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends GeneratedMessageInternal> messageClass,
+          final Class<? extends Builder> builderClass) {
+        super(descriptor, camelCaseName, messageClass, builderClass);
+
+        newBuilderMethod = getMethodOrDie(type, "newBuilder");
+        getBuilderMethodBuilder =
+            getMethodOrDie(builderClass, "get" + camelCaseName + "Builder", Integer.TYPE);
+      }
+
+      private final Method newBuilderMethod;
+      private final Method getBuilderMethodBuilder;
+
+      private Object coerceType(final Object value) {
+        if (type.isInstance(value)) {
+          return value;
+        } else {
+          // The value is not the exact right message type.  However, if it
+          // is an alternative implementation of the same type -- e.g. a
+          // DynamicMessage -- we should accept it.  In this case we can make
+          // a copy of the message.
+          return ((Message.Builder) invokeOrDie(newBuilderMethod, null))
+              .mergeFrom((Message) value)
+              .build();
+        }
+      }
+
+      @Override
+      public void setRepeated(final Builder builder, final int index, final Object value) {
+        super.setRepeated(builder, index, coerceType(value));
+      }
+
+      @Override
+      public void addRepeated(final Builder builder, final Object value) {
+        super.addRepeated(builder, coerceType(value));
+      }
+
+      @Override
+      public Message.Builder newBuilder() {
+        return (Message.Builder) invokeOrDie(newBuilderMethod, null);
+      }
+
+      @Override
+      public Message.Builder getRepeatedBuilder(
+          final GeneratedMessageInternal.Builder builder, final int index) {
+        return (Message.Builder) invokeOrDie(getBuilderMethodBuilder, builder, index);
+      }
+    }
+  }
+
+  /**
+   * Replaces this object in the output stream with a serialized form. Part of Java's serialization
+   * magic. Generated sub-classes must override this method by calling {@code return
+   * super.writeReplace();}
+   *
+   * @return a SerializedForm of this message
+   */
+  protected Object writeReplace() throws ObjectStreamException {
+    return new SerializedForm(this);
+  }
+
+  /**
+   * Checks that the {@link Extension} is non-Lite and returns it as a {@link GeneratedExtension}.
+   */
+  private static <MessageType extends ExtendableMessage<MessageType>, T>
+      Extension<MessageType, T> checkNotLite(ExtensionLite<MessageType, T> extension) {
+    if (extension.isLite()) {
+      throw new IllegalArgumentException("Expected non-lite extension.");
+    }
+
+    return (Extension<MessageType, T>) extension;
+  }
+
+  protected static int computeStringSize(final int fieldNumber, final Object value) {
+    if (value instanceof String) {
+      return CodedOutputStream.computeStringSize(fieldNumber, (String) value);
+    } else {
+      return CodedOutputStream.computeBytesSize(fieldNumber, (ByteString) value);
+    }
+  }
+
+  protected static int computeStringSizeNoTag(final Object value) {
+    if (value instanceof String) {
+      return CodedOutputStream.computeStringSizeNoTag((String) value);
+    } else {
+      return CodedOutputStream.computeBytesSizeNoTag((ByteString) value);
+    }
+  }
+
+  protected static void writeString(
+      CodedOutputStream output, final int fieldNumber, final Object value) throws IOException {
+    if (value instanceof String) {
+      output.writeString(fieldNumber, (String) value);
+    } else {
+      output.writeBytes(fieldNumber, (ByteString) value);
+    }
+  }
+
+  protected static void writeStringNoTag(CodedOutputStream output, final Object value)
+      throws IOException {
+    if (value instanceof String) {
+      output.writeStringNoTag((String) value);
+    } else {
+      output.writeBytesNoTag((ByteString) value);
+    }
+  }
+}
diff --git a/protobuf-api/src/main/java/com/google/protobuf/GeneratedMessageLite.java b/protobuf-api/src/main/java/com/google/protobuf/GeneratedMessageLite.java
index c153960..528636c 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/GeneratedMessageLite.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/GeneratedMessageLite.java
@@ -7,7 +7,6 @@
 
 package com.google.protobuf;
 
-import com.google.protobuf.AbstractMessageLite.Builder.LimitedInputStream;
 import com.google.protobuf.Internal.BooleanList;
 import com.google.protobuf.Internal.DoubleList;
 import com.google.protobuf.Internal.FloatList;
@@ -34,7 +33,7 @@
  *
  * @author kenton@google.com Kenton Varda
  */
-public abstract class GeneratedMessageLite<
+abstract class GeneratedMessageLite<
         MessageType extends GeneratedMessageLite<MessageType, BuilderType>,
         BuilderType extends GeneratedMessageLite.Builder<MessageType, BuilderType>>
     extends AbstractMessageLite<MessageType, BuilderType> {
@@ -623,7 +622,7 @@ protected <MessageType extends MessageLite> boolean parseUnknownField(
       // TODO: How much bytecode would be saved by not requiring the generated code to
       //     provide the default instance?
       GeneratedExtension<MessageType, ?> extension =
-          extensionRegistry.findLiteExtensionByNumber(defaultInstance, fieldNumber);
+              (GeneratedExtension<MessageType, ?>) extensionRegistry.findLiteExtensionByNumber(defaultInstance, fieldNumber);
 
       return parseExtension(input, extensionRegistry, extension, tag, fieldNumber);
     }
@@ -808,7 +807,7 @@ private <MessageType extends MessageLite> void mergeMessageSetExtensionFromCoded
         if (tag == WireFormat.MESSAGE_SET_TYPE_ID_TAG) {
           typeId = input.readUInt32();
           if (typeId != 0) {
-            extension = extensionRegistry.findLiteExtensionByNumber(defaultInstance, typeId);
+            extension = (GeneratedExtension<MessageType, ?>) extensionRegistry.findLiteExtensionByNumber(defaultInstance, typeId);
           }
 
         } else if (tag == WireFormat.MESSAGE_SET_MESSAGE_TAG) {
@@ -1395,93 +1394,6 @@ public Type getDefaultValue() {
     }
   }
 
-  /**
-   * A serialized (serializable) form of the generated message. Stores the message as a class name
-   * and a byte array.
-   */
-  protected static final class SerializedForm implements Serializable {
-
-    public static SerializedForm of(MessageLite message) {
-      return new SerializedForm(message);
-    }
-
-    private static final long serialVersionUID = 0L;
-
-    // since v3.6.1
-    private final Class<?> messageClass;
-    private final String messageClassName;
-    private final byte[] asBytes;
-
-    /**
-     * Creates the serialized form by calling {@link com.google.protobuf.MessageLite#toByteArray}.
-     *
-     * @param regularForm the message to serialize
-     */
-    SerializedForm(MessageLite regularForm) {
-      messageClass = regularForm.getClass();
-      messageClassName = regularForm.getClass().getName();
-      asBytes = regularForm.toByteArray();
-    }
-
-    /**
-     * When read from an ObjectInputStream, this method converts this object back to the regular
-     * form. Part of Java's serialization magic.
-     *
-     * @return a GeneratedMessage of the type that was serialized
-     */
-    protected Object readResolve() throws ObjectStreamException {
-      try {
-        Class<?> messageClass = resolveMessageClass();
-        java.lang.reflect.Field defaultInstanceField =
-            messageClass.getDeclaredField("DEFAULT_INSTANCE");
-        defaultInstanceField.setAccessible(true);
-        MessageLite defaultInstance = (MessageLite) defaultInstanceField.get(null);
-        return defaultInstance.newBuilderForType().mergeFrom(asBytes).buildPartial();
-      } catch (ClassNotFoundException e) {
-        throw new RuntimeException("Unable to find proto buffer class: " + messageClassName, e);
-      } catch (NoSuchFieldException e) {
-        return readResolveFallback();
-      } catch (SecurityException e) {
-        throw new RuntimeException("Unable to call DEFAULT_INSTANCE in " + messageClassName, e);
-      } catch (IllegalAccessException e) {
-        throw new RuntimeException("Unable to call parsePartialFrom", e);
-      } catch (InvalidProtocolBufferException e) {
-        throw new RuntimeException("Unable to understand proto buffer", e);
-      }
-    }
-
-    /**
-     * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1 generated code.
-     */
-    @Deprecated
-    private Object readResolveFallback() throws ObjectStreamException {
-      try {
-        Class<?> messageClass = resolveMessageClass();
-        java.lang.reflect.Field defaultInstanceField =
-            messageClass.getDeclaredField("defaultInstance");
-        defaultInstanceField.setAccessible(true);
-        MessageLite defaultInstance = (MessageLite) defaultInstanceField.get(null);
-        return defaultInstance.newBuilderForType()
-            .mergeFrom(asBytes)
-            .buildPartial();
-      } catch (ClassNotFoundException e) {
-        throw new RuntimeException("Unable to find proto buffer class: " + messageClassName, e);
-      } catch (NoSuchFieldException e) {
-        throw new RuntimeException("Unable to find defaultInstance in " + messageClassName, e);
-      } catch (SecurityException e) {
-        throw new RuntimeException("Unable to call defaultInstance in " + messageClassName, e);
-      } catch (IllegalAccessException e) {
-        throw new RuntimeException("Unable to call parsePartialFrom", e);
-      } catch (InvalidProtocolBufferException e) {
-        throw new RuntimeException("Unable to understand proto buffer", e);
-      }
-    }
-
-    private Class<?> resolveMessageClass() throws ClassNotFoundException {
-      return messageClass != null ? messageClass : Class.forName(messageClassName);
-    }
-  }
-
   /** Checks that the {@link Extension} is Lite and returns it as a {@link GeneratedExtension}. */
   private static <
           MessageType extends ExtendableMessage<MessageType, BuilderType>,
diff --git a/protobuf-api/src/main/java/com/google/protobuf/GeneratedMessageV3Internal.java b/protobuf-api/src/main/java/com/google/protobuf/GeneratedMessageV3Internal.java
new file mode 100644
index 0000000..5553325
--- /dev/null
+++ b/protobuf-api/src/main/java/com/google/protobuf/GeneratedMessageV3Internal.java
@@ -0,0 +1,3413 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+
+package com.google.protobuf;
+
+import com.google.protobuf.Descriptors.Descriptor;
+import com.google.protobuf.Descriptors.EnumDescriptor;
+import com.google.protobuf.Descriptors.EnumValueDescriptor;
+import com.google.protobuf.Descriptors.FieldDescriptor;
+import com.google.protobuf.Descriptors.FileDescriptor;
+import com.google.protobuf.Descriptors.OneofDescriptor;
+import com.google.protobuf.GeneratedMessageInternal.GeneratedExtension;
+import com.google.protobuf.Internal.BooleanList;
+import com.google.protobuf.Internal.DoubleList;
+import com.google.protobuf.Internal.FloatList;
+import com.google.protobuf.Internal.IntList;
+import com.google.protobuf.Internal.LongList;
+import com.google.protobuf.Internal.ProtobufList;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.ObjectStreamException;
+import java.io.Serializable;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+/**
+ * All generated protocol message classes extend this class. This class implements most of the
+ * Message and Builder interfaces using Java reflection. Users can ignore this class and pretend
+ * that generated messages implement the Message interface directly.
+ *
+ * @author kenton@google.com Kenton Varda
+ */
+abstract class GeneratedMessageV3Internal extends AbstractMessageInternal implements Serializable {
+  private static final long serialVersionUID = 1L;
+
+  /**
+   * For testing. Allows a test to disable the optimization that avoids using field builders for
+   * nested messages until they are requested. By disabling this optimization, existing tests can be
+   * reused to test the field builders.
+   */
+  protected static boolean alwaysUseFieldBuilders = false;
+
+  /**
+   * For use by generated code only.
+   *
+   * <p>TODO: mark this private and final (breaking change)
+   */
+  protected UnknownFieldSet unknownFields;
+
+  protected GeneratedMessageV3Internal() {
+    unknownFields = UnknownFieldSet.getDefaultInstance();
+  }
+
+  protected GeneratedMessageV3Internal(Builder<?> builder) {
+    unknownFields = builder.getUnknownFields();
+  }
+
+  /** TODO: Remove this unnecessary intermediate implementation of this method. */
+  @Override
+  public Parser<? extends GeneratedMessageV3Internal> getParserForType() {
+    throw new UnsupportedOperationException("This is supposed to be overridden by subclasses.");
+  }
+
+  /**
+   * TODO: Stop using SingleFieldBuilder and remove this setting
+   *
+   * @see #setAlwaysUseFieldBuildersForTesting(boolean)
+   */
+  static void enableAlwaysUseFieldBuildersForTesting() {
+    setAlwaysUseFieldBuildersForTesting(true);
+  }
+
+  /**
+   * For testing. Allows a test to disable/re-enable the optimization that avoids using field
+   * builders for nested messages until they are requested. By disabling this optimization, existing
+   * tests can be reused to test the field builders. See {@link RepeatedFieldBuilder} and {@link
+   * SingleFieldBuilder}.
+   *
+   * <p>TODO: Stop using SingleFieldBuilder and remove this setting
+   */
+  static void setAlwaysUseFieldBuildersForTesting(boolean useBuilders) {
+    alwaysUseFieldBuilders = useBuilders;
+  }
+
+  /**
+   * Get the FieldAccessorTable for this type. We can't have the message class pass this in to the
+   * constructor because of bootstrapping trouble with DescriptorProtos.
+   */
+  protected abstract FieldAccessorTable internalGetFieldAccessorTable();
+
+  @Override
+  public Descriptor getDescriptorForType() {
+    return internalGetFieldAccessorTable().descriptor;
+  }
+
+  /**
+   * TODO: This method should be removed. It enables parsing directly into an
+   * "immutable" message. Have to leave it for now to support old gencode.
+   *
+   * @deprecated use newBuilder().mergeFrom() instead
+   */
+  @Deprecated
+  protected void mergeFromAndMakeImmutableInternal(
+      CodedInputStream input, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    Schema<GeneratedMessageV3Internal> schema = Protobuf.getInstance().schemaFor(this);
+    try {
+      schema.mergeFrom(this, CodedInputStreamReader.forCodedInput(input), extensionRegistry);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.setUnfinishedMessage(this);
+    } catch (IOException e) {
+      throw new InvalidProtocolBufferException(e).setUnfinishedMessage(this);
+    }
+    schema.makeImmutable(this);
+  }
+
+  /**
+   * Internal helper to return a modifiable map containing all the fields. The returned Map is
+   * modifiable so that the caller can add additional extension fields to implement {@link
+   * #getAllFields()}.
+   *
+   * @param getBytesForString whether to generate ByteString for string fields
+   */
+  private Map<FieldDescriptor, Object> getAllFieldsMutable(boolean getBytesForString) {
+    final TreeMap<FieldDescriptor, Object> result = new TreeMap<>();
+    final Descriptor descriptor = internalGetFieldAccessorTable().descriptor;
+    final List<FieldDescriptor> fields = descriptor.getFields();
+
+    for (int i = 0; i < fields.size(); i++) {
+      FieldDescriptor field = fields.get(i);
+      final OneofDescriptor oneofDescriptor = field.getContainingOneof();
+
+      /*
+       * If the field is part of a Oneof, then at maximum one field in the Oneof is set
+       * and it is not repeated. There is no need to iterate through the others.
+       */
+      if (oneofDescriptor != null) {
+        // Skip other fields in the Oneof we know are not set
+        i += oneofDescriptor.getFieldCount() - 1;
+        if (!hasOneof(oneofDescriptor)) {
+          // If no field is set in the Oneof, skip all the fields in the Oneof
+          continue;
+        }
+        // Get the pointer to the only field which is set in the Oneof
+        field = getOneofFieldDescriptor(oneofDescriptor);
+      } else {
+        // If we are not in a Oneof, we need to check if the field is set and if it is repeated
+        if (field.isRepeated()) {
+          final List<?> value = (List<?>) getField(field);
+          if (!value.isEmpty()) {
+            result.put(field, value);
+          }
+          continue;
+        }
+        if (!hasField(field)) {
+          continue;
+        }
+      }
+      // Add the field to the map
+      if (getBytesForString && field.getJavaType() == FieldDescriptor.JavaType.STRING) {
+        result.put(field, getFieldRaw(field));
+      } else {
+        result.put(field, getField(field));
+      }
+    }
+    return result;
+  }
+
+  // TODO: compute this at {@code build()} time in the Builder class.
+  @Override
+  public boolean isInitialized() {
+    for (final FieldDescriptor field : getDescriptorForType().getFields()) {
+      // Check that all required fields are present.
+      if (field.isRequired()) {
+        if (!hasField(field)) {
+          return false;
+        }
+      }
+      // Check that embedded messages are initialized.
+      if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+        if (field.isRepeated()) {
+          @SuppressWarnings("unchecked")
+          final List<Message> messageList = (List<Message>) getField(field);
+          for (final Message element : messageList) {
+            if (!element.isInitialized()) {
+              return false;
+            }
+          }
+        } else {
+          if (hasField(field) && !((Message) getField(field)).isInitialized()) {
+            return false;
+          }
+        }
+      }
+    }
+
+    return true;
+  }
+
+  @Override
+  public Map<FieldDescriptor, Object> getAllFields() {
+    return Collections.unmodifiableMap(getAllFieldsMutable(/* getBytesForString= */ false));
+  }
+
+  /**
+   * Returns a collection of all the fields in this message which are set and their corresponding
+   * values. A singular ("required" or "optional") field is set iff hasField() returns true for that
+   * field. A "repeated" field is set iff getRepeatedFieldCount() is greater than zero. The values
+   * are exactly what would be returned by calling {@link #getFieldRaw(FieldDescriptor)}
+   * for each field. The map is guaranteed to be a sorted map, so iterating over it will return
+   * fields in order by field number.
+   */
+  Map<FieldDescriptor, Object> getAllFieldsRaw() {
+    return Collections.unmodifiableMap(getAllFieldsMutable(/* getBytesForString= */ true));
+  }
+
+  @Override
+  public boolean hasOneof(final OneofDescriptor oneof) {
+    return internalGetFieldAccessorTable().getOneof(oneof).has(this);
+  }
+
+  @Override
+  public FieldDescriptor getOneofFieldDescriptor(final OneofDescriptor oneof) {
+    return internalGetFieldAccessorTable().getOneof(oneof).get(this);
+  }
+
+  @Override
+  public boolean hasField(final FieldDescriptor field) {
+    return internalGetFieldAccessorTable().getField(field).has(this);
+  }
+
+  @Override
+  public Object getField(final FieldDescriptor field) {
+    return internalGetFieldAccessorTable().getField(field).get(this);
+  }
+
+  /**
+   * Obtains the value of the given field, or the default value if it is not set. For primitive
+   * fields, the boxed primitive value is returned. For enum fields, the EnumValueDescriptor for the
+   * value is returned. For embedded message fields, the sub-message is returned. For repeated
+   * fields, a java.util.List is returned. For present string fields, a ByteString is returned
+   * representing the bytes that the field contains.
+   */
+  Object getFieldRaw(final FieldDescriptor field) {
+    return internalGetFieldAccessorTable().getField(field).getRaw(this);
+  }
+
+  @Override
+  public int getRepeatedFieldCount(final FieldDescriptor field) {
+    return internalGetFieldAccessorTable().getField(field).getRepeatedCount(this);
+  }
+
+  @Override
+  public Object getRepeatedField(final FieldDescriptor field, final int index) {
+    return internalGetFieldAccessorTable().getField(field).getRepeated(this, index);
+  }
+
+  // TODO: This method should be final.
+  @Override
+  public UnknownFieldSet getUnknownFields() {
+    return unknownFields;
+  }
+
+  // TODO: This should go away when Schema classes cannot modify immutable
+  // GeneratedMessageV3Internal objects anymore.
+  void setUnknownFields(UnknownFieldSet unknownFields) {
+    this.unknownFields = unknownFields;
+  }
+
+  /**
+   * Called by subclasses to parse an unknown field.
+   *
+   * <p>TODO remove this method
+   *
+   * @return {@code true} unless the tag is an end-group tag.
+   */
+  protected boolean parseUnknownField(
+      CodedInputStream input,
+      UnknownFieldSet.Builder unknownFields,
+      ExtensionRegistryLite extensionRegistry,
+      int tag)
+      throws IOException {
+    if (input.shouldDiscardUnknownFields()) {
+      return input.skipField(tag);
+    }
+    return unknownFields.mergeFieldFrom(tag, input);
+  }
+
+  /**
+   * Delegates to parseUnknownField. This method is obsolete, but we must retain it for
+   * compatibility with older generated code.
+   *
+   * <p>TODO remove this method
+   */
+  protected boolean parseUnknownFieldProto3(
+      CodedInputStream input,
+      UnknownFieldSet.Builder unknownFields,
+      ExtensionRegistryLite extensionRegistry,
+      int tag)
+      throws IOException {
+    return parseUnknownField(input, unknownFields, extensionRegistry, tag);
+  }
+
+  /** Used by generated code. */
+  @SuppressWarnings("ProtoParseWithRegistry")
+  protected static <M extends Message> M parseWithIOException(Parser<M> parser, InputStream input)
+      throws IOException {
+    try {
+      return parser.parseFrom(input);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  /** Used by generated code. */
+  protected static <M extends Message> M parseWithIOException(
+      Parser<M> parser, InputStream input, ExtensionRegistryLite extensions) throws IOException {
+    try {
+      return parser.parseFrom(input, extensions);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  /** Used by generated code. */
+  @SuppressWarnings("ProtoParseWithRegistry")
+  protected static <M extends Message> M parseWithIOException(
+      Parser<M> parser, CodedInputStream input) throws IOException {
+    try {
+      return parser.parseFrom(input);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  /** Used by generated code. */
+  protected static <M extends Message> M parseWithIOException(
+      Parser<M> parser, CodedInputStream input, ExtensionRegistryLite extensions)
+      throws IOException {
+    try {
+      return parser.parseFrom(input, extensions);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  /** Used by generated code. */
+  @SuppressWarnings("ProtoParseWithRegistry")
+  protected static <M extends Message> M parseDelimitedWithIOException(
+      Parser<M> parser, InputStream input) throws IOException {
+    try {
+      return parser.parseDelimitedFrom(input);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  /** Used by generated code. */
+  protected static <M extends Message> M parseDelimitedWithIOException(
+      Parser<M> parser, InputStream input, ExtensionRegistryLite extensions) throws IOException {
+    try {
+      return parser.parseDelimitedFrom(input, extensions);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  protected static boolean canUseUnsafe() {
+    return UnsafeUtil.hasUnsafeArrayOperations() && UnsafeUtil.hasUnsafeByteBufferOperations();
+  }
+
+  protected static IntList emptyIntList() {
+    return IntArrayList.emptyList();
+  }
+
+  // TODO: Unused. Remove.
+  protected static IntList newIntList() {
+    return new IntArrayList();
+  }
+
+  // TODO: Redundant with makeMutableCopy(). Remove.
+  protected static IntList mutableCopy(IntList list) {
+    return makeMutableCopy(list);
+  }
+
+  // TODO: Redundant with makeMutableCopy(). Remove.
+  protected static LongList mutableCopy(LongList list) {
+    return makeMutableCopy(list);
+  }
+
+  // TODO: Redundant with makeMutableCopy(). Remove.
+  protected static FloatList mutableCopy(FloatList list) {
+    return makeMutableCopy(list);
+  }
+
+  // TODO: Redundant with makeMutableCopy(). Remove.
+  protected static DoubleList mutableCopy(DoubleList list) {
+    return makeMutableCopy(list);
+  }
+
+  // TODO: Redundant with makeMutableCopy(). Remove.
+  protected static BooleanList mutableCopy(BooleanList list) {
+    return makeMutableCopy(list);
+  }
+
+  protected static LongList emptyLongList() {
+    return LongArrayList.emptyList();
+  }
+
+  // TODO: Unused. Remove.
+  protected static LongList newLongList() {
+    return new LongArrayList();
+  }
+
+  protected static FloatList emptyFloatList() {
+    return FloatArrayList.emptyList();
+  }
+
+  // TODO: Unused. Remove.
+  protected static FloatList newFloatList() {
+    return new FloatArrayList();
+  }
+
+  protected static DoubleList emptyDoubleList() {
+    return DoubleArrayList.emptyList();
+  }
+
+  // TODO: Unused. Remove.
+  protected static DoubleList newDoubleList() {
+    return new DoubleArrayList();
+  }
+
+  protected static BooleanList emptyBooleanList() {
+    return BooleanArrayList.emptyList();
+  }
+
+  // TODO: Unused. Remove.
+  protected static BooleanList newBooleanList() {
+    return new BooleanArrayList();
+  }
+
+  protected static <ListT extends ProtobufList<?>> ListT makeMutableCopy(ListT list) {
+    return makeMutableCopy(list, 0);
+  }
+
+  @SuppressWarnings("unchecked") // Guaranteed by proto runtime.
+  protected static <ListT extends ProtobufList<?>> ListT makeMutableCopy(
+      ListT list, int minCapacity) {
+    int size = list.size();
+    if (minCapacity <= size) {
+      minCapacity = size * 2;
+    }
+    if (minCapacity <= 0) {
+      minCapacity = AbstractProtobufList.DEFAULT_CAPACITY;
+    }
+
+    return (ListT) list.mutableCopyWithCapacity(minCapacity);
+  }
+
+  @SuppressWarnings("unchecked") // The empty list can be safely cast
+  protected static <T> ProtobufList<T> emptyList(Class<T> elementType) {
+    return (ProtobufList<T>) ProtobufArrayList.emptyList();
+  }
+
+  @Override
+  public void writeTo(final CodedOutputStream output) throws IOException {
+    MessageReflection.writeMessageTo(this, getAllFieldsRaw(), output, false);
+  }
+
+  @Override
+  public int getSerializedSize() {
+    int size = memoizedSize;
+    if (size != -1) {
+      return size;
+    }
+
+    memoizedSize = MessageReflection.getSerializedSize(
+        this, getAllFieldsRaw());
+    return memoizedSize;
+  }
+
+  /**
+   * This class is used to make a generated protected method inaccessible from user's code (e.g.,
+   * the {@link #newInstance} method below). When this class is used as a parameter's type in a
+   * generated protected method, the method is visible to user's code in the same package, but since
+   * the constructor of this class is private to protobuf runtime, user's code can't obtain an
+   * instance of this class and as such can't actually make a method call on the protected method.
+   */
+  protected static final class UnusedPrivateParameter {
+    static final UnusedPrivateParameter INSTANCE = new UnusedPrivateParameter();
+
+    private UnusedPrivateParameter() {}
+  }
+
+  /** Creates a new instance of this message type. Overridden in the generated code. */
+  @SuppressWarnings({"unused"})
+  protected Object newInstance(UnusedPrivateParameter unused) {
+    throw new UnsupportedOperationException("This method must be overridden by the subclass.");
+  }
+
+  /**
+   * Used by parsing constructors in generated classes.
+   *
+   * <p>TODO: remove unused method (extensions should be immutable after build)
+   */
+  protected void makeExtensionsImmutable() {
+    // Noop for messages without extensions.
+  }
+
+  /**
+   * TODO: remove this after b/29368482 is fixed. We need to move this interface to
+   * AbstractMessage in order to versioning GeneratedMessageV3Internal but this move breaks binary
+   * compatibility for AppEngine. After AppEngine is fixed we can exclude this from google3.
+   *
+   * <p>TODO: Remove at breaking change since b/29368482 was fixed in 2020
+   */
+  protected interface BuilderParent extends AbstractMessageInternal.BuilderParent {}
+
+  /** TODO: remove this together with GeneratedMessageV3Internal.BuilderParent. */
+  protected abstract Message.Builder newBuilderForType(BuilderParent parent);
+
+  /** TODO: generated class should implement this directly */
+  public Message.Builder newBuilderForType(final Message.BuilderParent parent) {
+    return newBuilderForType(
+        new BuilderParent() {
+          @Override
+          public void markDirty() {
+            parent.markDirty();
+          }
+        });
+  }
+
+  /** Builder class for {@link GeneratedMessageV3Internal}. */
+  @SuppressWarnings("unchecked")
+  public abstract static class Builder<BuilderT extends Builder<BuilderT>>
+      extends AbstractMessageInternal.Builder<BuilderT> {
+
+    private BuilderParent builderParent;
+
+    private BuilderParentImpl meAsParent;
+
+    // Indicates that we've built a message and so we are now obligated
+    // to dispatch dirty invalidations. See GeneratedMessageV3Internal.BuilderListener.
+    private boolean isClean;
+
+    /**
+     * This field holds either an {@link UnknownFieldSet} or {@link UnknownFieldSet.Builder}.
+     *
+     * <p>We use an object because it should only be one or the other of those things at a time and
+     * Object is the only common base. This also saves space.
+     *
+     * <p>Conversions are lazy: if {@link #setUnknownFields} is called, this will contain {@link
+     * UnknownFieldSet}. If unknown fields are merged into this builder, the current {@link
+     * UnknownFieldSet} will be converted to a {@link UnknownFieldSet.Builder} and left that way
+     * until either {@link #setUnknownFields} or {@link #buildPartial} or {@link #build} is called.
+     */
+    private Object unknownFieldsOrBuilder = UnknownFieldSet.getDefaultInstance();
+
+    protected Builder() {
+      this(null);
+    }
+
+    protected Builder(BuilderParent builderParent) {
+      this.builderParent = builderParent;
+    }
+
+    @Override
+    public void dispose() {
+      builderParent = null;
+    }
+
+    /** Called by the subclass when a message is built. */
+    protected void onBuilt() {
+      if (builderParent != null) {
+        markClean();
+      }
+    }
+
+    /**
+     * Called by the subclass or a builder to notify us that a message was built and may be cached
+     * and therefore invalidations are needed.
+     */
+    @Override
+    public void markClean() {
+      this.isClean = true;
+    }
+
+    /**
+     * Gets whether invalidations are needed
+     *
+     * @return whether invalidations are needed
+     */
+    protected boolean isClean() {
+      return isClean;
+    }
+
+    @Override
+    public BuilderT clone() {
+      BuilderT builder = (BuilderT) getDefaultInstanceForType().newBuilderForType();
+      builder.mergeFrom(buildPartial());
+      return builder;
+    }
+
+    /**
+     * Called by the initialization and clear code paths to allow subclasses to reset any of their
+     * builtin fields back to the initial values.
+     */
+    @Override
+    public BuilderT clear() {
+      unknownFieldsOrBuilder = UnknownFieldSet.getDefaultInstance();
+      onChanged();
+      return (BuilderT) this;
+    }
+
+    /**
+     * Get the FieldAccessorTable for this type. We can't have the message class pass this in to the
+     * constructor because of bootstrapping trouble with DescriptorProtos.
+     */
+    protected abstract FieldAccessorTable internalGetFieldAccessorTable();
+
+    @Override
+    public Descriptor getDescriptorForType() {
+      return internalGetFieldAccessorTable().descriptor;
+    }
+
+    @Override
+    public Map<FieldDescriptor, Object> getAllFields() {
+      return Collections.unmodifiableMap(getAllFieldsMutable());
+    }
+
+    /** Internal helper which returns a mutable map. */
+    private Map<FieldDescriptor, Object> getAllFieldsMutable() {
+      final TreeMap<FieldDescriptor, Object> result = new TreeMap<>();
+      final Descriptor descriptor = internalGetFieldAccessorTable().descriptor;
+      final List<FieldDescriptor> fields = descriptor.getFields();
+
+      for (int i = 0; i < fields.size(); i++) {
+        FieldDescriptor field = fields.get(i);
+        final OneofDescriptor oneofDescriptor = field.getContainingOneof();
+
+        /*
+         * If the field is part of a Oneof, then at maximum one field in the Oneof is set
+         * and it is not repeated. There is no need to iterate through the others.
+         */
+        if (oneofDescriptor != null) {
+          // Skip other fields in the Oneof we know are not set
+          i += oneofDescriptor.getFieldCount() - 1;
+          if (!hasOneof(oneofDescriptor)) {
+            // If no field is set in the Oneof, skip all the fields in the Oneof
+            continue;
+          }
+          // Get the pointer to the only field which is set in the Oneof
+          field = getOneofFieldDescriptor(oneofDescriptor);
+        } else {
+          // If we are not in a Oneof, we need to check if the field is set and if it is repeated
+          if (field.isRepeated()) {
+            final List<?> value = (List<?>) getField(field);
+            if (!value.isEmpty()) {
+              result.put(field, value);
+            }
+            continue;
+          }
+          if (!hasField(field)) {
+            continue;
+          }
+        }
+        // Add the field to the map
+        result.put(field, getField(field));
+      }
+      return result;
+    }
+
+    @Override
+    public Message.Builder newBuilderForField(final FieldDescriptor field) {
+      return internalGetFieldAccessorTable().getField(field).newBuilder();
+    }
+
+    @Override
+    public Message.Builder getFieldBuilder(final FieldDescriptor field) {
+      return internalGetFieldAccessorTable().getField(field).getBuilder(this);
+    }
+
+    @Override
+    public Message.Builder getRepeatedFieldBuilder(final FieldDescriptor field, int index) {
+      return internalGetFieldAccessorTable().getField(field).getRepeatedBuilder(this, index);
+    }
+
+    @Override
+    public boolean hasOneof(final OneofDescriptor oneof) {
+      return internalGetFieldAccessorTable().getOneof(oneof).has(this);
+    }
+
+    @Override
+    public FieldDescriptor getOneofFieldDescriptor(final OneofDescriptor oneof) {
+      return internalGetFieldAccessorTable().getOneof(oneof).get(this);
+    }
+
+    @Override
+    public boolean hasField(final FieldDescriptor field) {
+      return internalGetFieldAccessorTable().getField(field).has(this);
+    }
+
+    @Override
+    public Object getField(final FieldDescriptor field) {
+      Object object = internalGetFieldAccessorTable().getField(field).get(this);
+      if (field.isRepeated()) {
+        // The underlying list object is still modifiable at this point.
+        // Make sure not to expose the modifiable list to the caller.
+        return Collections.unmodifiableList((List<?>) object);
+      } else {
+        return object;
+      }
+    }
+
+    @Override
+    public BuilderT setField(final FieldDescriptor field, final Object value) {
+      internalGetFieldAccessorTable().getField(field).set(this, value);
+      return (BuilderT) this;
+    }
+
+    @Override
+    public BuilderT clearField(final FieldDescriptor field) {
+      internalGetFieldAccessorTable().getField(field).clear(this);
+      return (BuilderT) this;
+    }
+
+    @Override
+    public BuilderT clearOneof(final OneofDescriptor oneof) {
+      internalGetFieldAccessorTable().getOneof(oneof).clear(this);
+      return (BuilderT) this;
+    }
+
+    @Override
+    public int getRepeatedFieldCount(final FieldDescriptor field) {
+      return internalGetFieldAccessorTable().getField(field).getRepeatedCount(this);
+    }
+
+    @Override
+    public Object getRepeatedField(final FieldDescriptor field, final int index) {
+      return internalGetFieldAccessorTable().getField(field).getRepeated(this, index);
+    }
+
+    @Override
+    public BuilderT setRepeatedField(
+        final FieldDescriptor field, final int index, final Object value) {
+      internalGetFieldAccessorTable().getField(field).setRepeated(this, index, value);
+      return (BuilderT) this;
+    }
+
+    @Override
+    public BuilderT addRepeatedField(final FieldDescriptor field, final Object value) {
+      internalGetFieldAccessorTable().getField(field).addRepeated(this, value);
+      return (BuilderT) this;
+    }
+
+    private BuilderT setUnknownFieldsInternal(final UnknownFieldSet unknownFields) {
+      unknownFieldsOrBuilder = unknownFields;
+      onChanged();
+      return (BuilderT) this;
+    }
+
+    @Override
+    public BuilderT setUnknownFields(final UnknownFieldSet unknownFields) {
+      return setUnknownFieldsInternal(unknownFields);
+    }
+
+    /**
+     * This method is obsolete, but we must retain it for compatibility with older generated code.
+     */
+    protected BuilderT setUnknownFieldsProto3(final UnknownFieldSet unknownFields) {
+      return setUnknownFieldsInternal(unknownFields);
+    }
+
+    @Override
+    public BuilderT mergeUnknownFields(final UnknownFieldSet unknownFields) {
+      if (UnknownFieldSet.getDefaultInstance().equals(unknownFields)) {
+        return (BuilderT) this;
+      }
+
+      if (UnknownFieldSet.getDefaultInstance().equals(unknownFieldsOrBuilder)) {
+        unknownFieldsOrBuilder = unknownFields;
+        onChanged();
+        return (BuilderT) this;
+      }
+
+      getUnknownFieldSetBuilder().mergeFrom(unknownFields);
+      onChanged();
+      return (BuilderT) this;
+    }
+
+    @Override
+    public boolean isInitialized() {
+      for (final FieldDescriptor field : getDescriptorForType().getFields()) {
+        // Check that all required fields are present.
+        if (field.isRequired()) {
+          if (!hasField(field)) {
+            return false;
+          }
+        }
+        // Check that embedded messages are initialized.
+        if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+          if (field.isRepeated()) {
+            @SuppressWarnings("unchecked")
+            final List<Message> messageList = (List<Message>) getField(field);
+            for (final Message element : messageList) {
+              if (!element.isInitialized()) {
+                return false;
+              }
+            }
+          } else {
+            if (hasField(field) && !((Message) getField(field)).isInitialized()) {
+              return false;
+            }
+          }
+        }
+      }
+      return true;
+    }
+
+    @Override
+    public final UnknownFieldSet getUnknownFields() {
+      if (unknownFieldsOrBuilder instanceof UnknownFieldSet) {
+        return (UnknownFieldSet) unknownFieldsOrBuilder;
+      } else {
+        return ((UnknownFieldSet.Builder) unknownFieldsOrBuilder).buildPartial();
+      }
+    }
+
+    /**
+     * Called by generated subclasses to parse an unknown field.
+     *
+     * @return {@code true} unless the tag is an end-group tag.
+     */
+    protected boolean parseUnknownField(
+        CodedInputStream input, ExtensionRegistryLite extensionRegistry, int tag)
+        throws IOException {
+      if (input.shouldDiscardUnknownFields()) {
+        return input.skipField(tag);
+      }
+      return getUnknownFieldSetBuilder().mergeFieldFrom(tag, input);
+    }
+
+    /** Called by generated subclasses to add to the unknown field set. */
+    protected final void mergeUnknownLengthDelimitedField(int number, ByteString bytes) {
+      getUnknownFieldSetBuilder().mergeLengthDelimitedField(number, bytes);
+    }
+
+    /** Called by generated subclasses to add to the unknown field set. */
+    protected final void mergeUnknownVarintField(int number, int value) {
+      getUnknownFieldSetBuilder().mergeVarintField(number, value);
+    }
+
+    @Override
+    protected UnknownFieldSet.Builder getUnknownFieldSetBuilder() {
+      if (unknownFieldsOrBuilder instanceof UnknownFieldSet) {
+        unknownFieldsOrBuilder = ((UnknownFieldSet) unknownFieldsOrBuilder).toBuilder();
+      }
+      onChanged();
+      return (UnknownFieldSet.Builder) unknownFieldsOrBuilder;
+    }
+
+    @Override
+    protected void setUnknownFieldSetBuilder(UnknownFieldSet.Builder builder) {
+      unknownFieldsOrBuilder = builder;
+      onChanged();
+    }
+
+    /**
+     * Implementation of {@link BuilderParent} for giving to our children. This small inner class
+     * makes it so we don't publicly expose the BuilderParent methods.
+     */
+    private class BuilderParentImpl implements BuilderParent {
+
+      @Override
+      public void markDirty() {
+        onChanged();
+      }
+    }
+
+    /**
+     * Gets the {@link BuilderParent} for giving to our children.
+     *
+     * @return The builder parent for our children.
+     */
+    protected BuilderParent getParentForChildren() {
+      if (meAsParent == null) {
+        meAsParent = new BuilderParentImpl();
+      }
+      return meAsParent;
+    }
+
+    /**
+     * Called when a builder or one of its nested children has changed and any parent should be
+     * notified of its invalidation.
+     */
+    protected final void onChanged() {
+      if (isClean && builderParent != null) {
+        builderParent.markDirty();
+
+        // Don't keep dispatching invalidations until build is called again.
+        isClean = false;
+      }
+    }
+
+    /**
+     * Gets the map field with the given field number. This method should be overridden in the
+     * generated message class if the message contains map fields.
+     *
+     * <p>Unlike other field types, reflection support for map fields can't be implemented based on
+     * generated public API because we need to access a map field as a list in reflection API but
+     * the generated API only allows us to access it as a map. This method returns the underlying
+     * map field directly and thus enables us to access the map field as a list.
+     */
+    @SuppressWarnings({"unused", "rawtypes"})
+    protected MapFieldReflectionAccessor internalGetMapFieldReflection(int fieldNumber) {
+      return internalGetMapField(fieldNumber);
+    }
+
+    /** TODO: Remove, exists for compatibility with generated code. */
+    @Deprecated
+    @SuppressWarnings({"unused", "rawtypes"})
+    protected MapField internalGetMapField(int fieldNumber) {
+      // Note that we can't use descriptor names here because this method will
+      // be called when descriptor is being initialized.
+      throw new IllegalArgumentException("No map fields found in " + getClass().getName());
+    }
+
+    /** Like {@link #internalGetMapFieldReflection} but return a mutable version. */
+    @SuppressWarnings({"unused", "rawtypes"})
+    protected MapFieldReflectionAccessor internalGetMutableMapFieldReflection(int fieldNumber) {
+      return internalGetMutableMapField(fieldNumber);
+    }
+
+    /** TODO: Remove, exists for compatibility with generated code. */
+    @Deprecated
+    @SuppressWarnings({"unused", "rawtypes"})
+    protected MapField internalGetMutableMapField(int fieldNumber) {
+      // Note that we can't use descriptor names here because this method will
+      // be called when descriptor is being initialized.
+      throw new IllegalArgumentException("No map fields found in " + getClass().getName());
+    }
+  }
+
+  // =================================================================
+  // Extensions-related stuff
+
+  /** Extends {@link MessageOrBuilder} with extension-related functions. */
+  public interface ExtendableMessageOrBuilder<MessageT extends ExtendableMessage<MessageT>>
+      extends MessageOrBuilder {
+    // Re-define for return type covariance.
+    @Override
+    Message getDefaultInstanceForType();
+
+    /** Check if a singular extension is present. */
+    <T> boolean hasExtension(ExtensionLite<MessageT, T> extension);
+
+    /** Get the number of elements in a repeated extension. */
+    <T> int getExtensionCount(ExtensionLite<MessageT, List<T>> extension);
+
+    /** Get the value of an extension. */
+    <T> T getExtension(ExtensionLite<MessageT, T> extension);
+
+    /** Get one element of a repeated extension. */
+    <T> T getExtension(ExtensionLite<MessageT, List<T>> extension, int index);
+
+    /**
+     * Check if a singular extension is present.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    <T> boolean hasExtension(
+        Extension<MessageT, T> extension);
+    /**
+     * Check if a singular extension is present.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    <T> boolean hasExtension(
+        GeneratedExtension<MessageT, T> extension);
+    /**
+     * Get the number of elements in a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    <T> int getExtensionCount(
+        Extension<MessageT, List<T>> extension);
+    /**
+     * Get the number of elements in a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    <T> int getExtensionCount(
+        GeneratedExtension<MessageT, List<T>> extension);
+    /**
+     * Get the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    <T> T getExtension(
+        Extension<MessageT, T> extension);
+    /**
+     * Get the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    <T> T getExtension(
+        GeneratedExtension<MessageT, T> extension);
+    /**
+     * Get one element of a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    <T> T getExtension(
+        Extension<MessageT, List<T>> extension,
+        int index);
+    /**
+     * Get one element of a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    <T> T getExtension(
+        GeneratedExtension<MessageT, List<T>> extension,
+        int index);
+  }
+
+  /**
+   * Generated message classes for message types that contain extension ranges subclass this.
+   *
+   * <p>This class implements type-safe accessors for extensions. They implement all the same
+   * operations that you can do with normal fields -- e.g. "has", "get", and "getCount" -- but for
+   * extensions. The extensions are identified using instances of the class {@link
+   * GeneratedExtension}; the protocol compiler generates a static instance of this class for every
+   * extension in its input. Through the magic of generics, all is made type-safe.
+   *
+   * <p>For example, imagine you have the {@code .proto} file:
+   *
+   * <pre>
+   * option java_class = "MyProto";
+   *
+   * message Foo {
+   *   extensions 1000 to max;
+   * }
+   *
+   * extend Foo {
+   *   optional int32 bar;
+   * }
+   * </pre>
+   *
+   * <p>Then you might write code like:
+   *
+   * <pre>
+   * MyProto.Foo foo = getFoo();
+   * int i = foo.getExtension(MyProto.bar);
+   * </pre>
+   *
+   * <p>See also {@link ExtendableBuilder}.
+   */
+  public abstract static class ExtendableMessage<MessageT extends ExtendableMessage<MessageT>>
+      extends GeneratedMessageV3Internal implements ExtendableMessageOrBuilder<MessageT> {
+
+    private static final long serialVersionUID = 1L;
+
+    private final FieldSet<FieldDescriptor> extensions;
+
+    protected ExtendableMessage() {
+      this.extensions = FieldSet.newFieldSet();
+    }
+
+    protected ExtendableMessage(ExtendableBuilder<MessageT, ?> builder) {
+      super(builder);
+      this.extensions = builder.buildExtensions();
+    }
+
+    private void verifyExtensionContainingType(final Extension<MessageT, ?> extension) {
+      if (extension.getDescriptor().getContainingType() != getDescriptorForType()) {
+        // This can only happen if someone uses unchecked operations.
+        throw new IllegalArgumentException(
+            "Extension is for type \""
+                + extension.getDescriptor().getContainingType().getFullName()
+                + "\" which does not match message type \""
+                + getDescriptorForType().getFullName()
+                + "\".");
+      }
+    }
+
+    /** Check if a singular extension is present. */
+    @Override
+    public final <T> boolean hasExtension(final ExtensionLite<MessageT, T> extensionLite) {
+      Extension<MessageT, T> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      return extensions.hasField(extension.getDescriptor());
+    }
+
+    /** Get the number of elements in a repeated extension. */
+    @Override
+    public final <T> int getExtensionCount(final ExtensionLite<MessageT, List<T>> extensionLite) {
+      Extension<MessageT, List<T>> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      final FieldDescriptor descriptor = extension.getDescriptor();
+      return extensions.getRepeatedFieldCount(descriptor);
+    }
+
+    /** Get the value of an extension. */
+    @Override
+    @SuppressWarnings("unchecked")
+    public final <T> T getExtension(final ExtensionLite<MessageT, T> extensionLite) {
+      Extension<MessageT, T> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      FieldDescriptor descriptor = extension.getDescriptor();
+      final Object value = extensions.getField(descriptor);
+      if (value == null) {
+        if (descriptor.isRepeated()) {
+          return (T) Collections.emptyList();
+        } else if (descriptor.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+          return (T) extension.getMessageDefaultInstance();
+        } else {
+          return (T) extension.fromReflectionType(descriptor.getDefaultValue());
+        }
+      } else {
+        return (T) extension.fromReflectionType(value);
+      }
+    }
+
+    /** Get one element of a repeated extension. */
+    @Override
+    @SuppressWarnings("unchecked")
+    public final <T> T getExtension(
+        final ExtensionLite<MessageT, List<T>> extensionLite, final int index) {
+      Extension<MessageT, List<T>> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      FieldDescriptor descriptor = extension.getDescriptor();
+      return (T)
+          extension.singularFromReflectionType(extensions.getRepeatedField(descriptor, index));
+    }
+
+    /**
+     * Check if a singular extension is present.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> boolean hasExtension(final Extension<MessageT, T> extension) {
+      return hasExtension((ExtensionLite<MessageT, T>) extension);
+    }
+    /**
+     * Check if a singular extension is present.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> boolean hasExtension(
+        final GeneratedExtension<MessageT, T> extension) {
+      return hasExtension((ExtensionLite<MessageT, T>) extension);
+    }
+    /**
+     * Get the number of elements in a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> int getExtensionCount(
+        final Extension<MessageT, List<T>> extension) {
+      return getExtensionCount((ExtensionLite<MessageT, List<T>>) extension);
+    }
+    /**
+     * Get the number of elements in a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> int getExtensionCount(
+        final GeneratedExtension<MessageT, List<T>> extension) {
+      return getExtensionCount((ExtensionLite<MessageT, List<T>>) extension);
+    }
+    /**
+     * Get the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> T getExtension(final Extension<MessageT, T> extension) {
+      return getExtension((ExtensionLite<MessageT, T>) extension);
+    }
+    /**
+     * Get the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> T getExtension(
+        final GeneratedExtension<MessageT, T> extension) {
+      return getExtension((ExtensionLite<MessageT, T>) extension);
+    }
+    /**
+     * Get one element of a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> T getExtension(
+        final Extension<MessageT, List<T>> extension, final int index) {
+      return getExtension((ExtensionLite<MessageT, List<T>>) extension, index);
+    }
+    /**
+     * Get one element of a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> T getExtension(
+        final GeneratedExtension<MessageT, List<T>> extension, final int index) {
+      return getExtension((ExtensionLite<MessageT, List<T>>) extension, index);
+    }
+
+    /** Called by subclasses to check if all extensions are initialized. */
+    protected boolean extensionsAreInitialized() {
+      return extensions.isInitialized();
+    }
+
+    // TODO: compute this in the builder at {@code build()} time.
+    @Override
+    public boolean isInitialized() {
+      return super.isInitialized() && extensionsAreInitialized();
+    }
+
+    // TODO: remove mutating method from immutable type
+    @Override
+    protected boolean parseUnknownField(
+        CodedInputStream input,
+        UnknownFieldSet.Builder unknownFields,
+        ExtensionRegistryLite extensionRegistry,
+        int tag)
+        throws IOException {
+      return MessageReflection.mergeFieldFrom(
+          input,
+          input.shouldDiscardUnknownFields() ? null : unknownFields,
+          extensionRegistry,
+          getDescriptorForType(),
+          new MessageReflection.ExtensionAdapter(extensions),
+          tag);
+    }
+
+    /**
+     * Delegates to parseUnknownField. This method is obsolete, but we must retain it for
+     * compatibility with older generated code.
+     *
+     * <p>TODO: remove mutating method from immutable type
+     */
+    @Override
+    protected boolean parseUnknownFieldProto3(
+        CodedInputStream input,
+        UnknownFieldSet.Builder unknownFields,
+        ExtensionRegistryLite extensionRegistry,
+        int tag)
+        throws IOException {
+      return parseUnknownField(input, unknownFields, extensionRegistry, tag);
+    }
+
+    /**
+     * Used by parsing constructors in generated classes.
+     *
+     * <p>TODO: remove unused method (extensions should be immutable after build)
+     */
+    @Override
+    protected void makeExtensionsImmutable() {
+      extensions.makeImmutable();
+    }
+
+    /**
+     * Used by subclasses to serialize extensions. Extension ranges may be interleaved with field
+     * numbers, but we must write them in canonical (sorted by field number) order. ExtensionWriter
+     * helps us write individual ranges of extensions at once.
+     */
+    protected class ExtensionWriter {
+      // Imagine how much simpler this code would be if Java iterators had
+      // a way to get the next element without advancing the iterator.
+
+      private final Iterator<Map.Entry<FieldDescriptor, Object>> iter = extensions.iterator();
+      private Map.Entry<FieldDescriptor, Object> next;
+      private final boolean messageSetWireFormat;
+
+      private ExtensionWriter(final boolean messageSetWireFormat) {
+        if (iter.hasNext()) {
+          next = iter.next();
+        }
+        this.messageSetWireFormat = messageSetWireFormat;
+      }
+
+      public void writeUntil(final int end, final CodedOutputStream output) throws IOException {
+        while (next != null && next.getKey().getNumber() < end) {
+          FieldDescriptor descriptor = next.getKey();
+          if (messageSetWireFormat
+              && descriptor.getLiteJavaType() == WireFormat.JavaType.MESSAGE
+              && !descriptor.isRepeated()) {
+            if (next instanceof LazyField.LazyEntry<?>) {
+              output.writeRawMessageSetExtension(
+                  descriptor.getNumber(),
+                  ((LazyField.LazyEntry<?>) next).getField().toByteString());
+            } else {
+              output.writeMessageSetExtension(descriptor.getNumber(), (Message) next.getValue());
+            }
+          } else {
+            // TODO: Taken care of following code, it may cause
+            // problem when we use LazyField for normal fields/extensions.
+            // Due to the optional field can be duplicated at the end of
+            // serialized bytes, which will make the serialized size change
+            // after lazy field parsed. So when we use LazyField globally,
+            // we need to change the following write method to write cached
+            // bytes directly rather than write the parsed message.
+            FieldSet.writeField(descriptor, next.getValue(), output);
+          }
+          if (iter.hasNext()) {
+            next = iter.next();
+          } else {
+            next = null;
+          }
+        }
+      }
+    }
+
+    protected ExtensionWriter newExtensionWriter() {
+      return new ExtensionWriter(false);
+    }
+
+    protected ExtensionWriter newMessageSetExtensionWriter() {
+      return new ExtensionWriter(true);
+    }
+
+    /** Called by subclasses to compute the size of extensions. */
+    protected int extensionsSerializedSize() {
+      return extensions.getSerializedSize();
+    }
+
+    protected int extensionsSerializedSizeAsMessageSet() {
+      return extensions.getMessageSetSerializedSize();
+    }
+
+    // ---------------------------------------------------------------
+    // Reflection
+
+    protected Map<FieldDescriptor, Object> getExtensionFields() {
+      return extensions.getAllFields();
+    }
+
+    @Override
+    public Map<FieldDescriptor, Object> getAllFields() {
+      final Map<FieldDescriptor, Object> result =
+          super.getAllFieldsMutable(/* getBytesForString= */ false);
+      result.putAll(getExtensionFields());
+      return Collections.unmodifiableMap(result);
+    }
+
+    @Override
+    public Map<FieldDescriptor, Object> getAllFieldsRaw() {
+      final Map<FieldDescriptor, Object> result =
+          super.getAllFieldsMutable(/* getBytesForString= */ false);
+      result.putAll(getExtensionFields());
+      return Collections.unmodifiableMap(result);
+    }
+
+    @Override
+    public boolean hasField(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        return extensions.hasField(field);
+      } else {
+        return super.hasField(field);
+      }
+    }
+
+    @Override
+    public Object getField(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        final Object value = extensions.getField(field);
+        if (value == null) {
+          if (field.isRepeated()) {
+            return Collections.emptyList();
+          } else if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+            // Lacking an ExtensionRegistry, we have no way to determine the
+            // extension's real type, so we return a DynamicMessage.
+            return DynamicMessage.getDefaultInstance(field.getMessageType());
+          } else {
+            return field.getDefaultValue();
+          }
+        } else {
+          return value;
+        }
+      } else {
+        return super.getField(field);
+      }
+    }
+
+    @Override
+    public int getRepeatedFieldCount(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        return extensions.getRepeatedFieldCount(field);
+      } else {
+        return super.getRepeatedFieldCount(field);
+      }
+    }
+
+    @Override
+    public Object getRepeatedField(final FieldDescriptor field, final int index) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        return extensions.getRepeatedField(field, index);
+      } else {
+        return super.getRepeatedField(field, index);
+      }
+    }
+
+    private void verifyContainingType(final FieldDescriptor field) {
+      if (field.getContainingType() != getDescriptorForType()) {
+        throw new IllegalArgumentException("FieldDescriptor does not match message type.");
+      }
+    }
+  }
+
+  /**
+   * Generated message builders for message types that contain extension ranges subclass this.
+   *
+   * <p>This class implements type-safe accessors for extensions. They implement all the same
+   * operations that you can do with normal fields -- e.g. "get", "set", and "add" -- but for
+   * extensions. The extensions are identified using instances of the class {@link
+   * GeneratedExtension}; the protocol compiler generates a static instance of this class for every
+   * extension in its input. Through the magic of generics, all is made type-safe.
+   *
+   * <p>For example, imagine you have the {@code .proto} file:
+   *
+   * <pre>
+   * option java_class = "MyProto";
+   *
+   * message Foo {
+   *   extensions 1000 to max;
+   * }
+   *
+   * extend Foo {
+   *   optional int32 bar;
+   * }
+   * </pre>
+   *
+   * <p>Then you might write code like:
+   *
+   * <pre>
+   * MyProto.Foo foo =
+   *   MyProto.Foo.newBuilder()
+   *     .setExtension(MyProto.bar, 123)
+   *     .build();
+   * </pre>
+   *
+   * <p>See also {@link ExtendableMessage}.
+   */
+  @SuppressWarnings("unchecked")
+  public abstract static class ExtendableBuilder<
+          MessageT extends ExtendableMessage<MessageT>,
+          BuilderT extends ExtendableBuilder<MessageT, BuilderT>>
+      extends Builder<BuilderT> implements ExtendableMessageOrBuilder<MessageT> {
+
+    private FieldSet.Builder<FieldDescriptor> extensions;
+
+    protected ExtendableBuilder() {}
+
+    protected ExtendableBuilder(BuilderParent parent) {
+      super(parent);
+    }
+
+    // For immutable message conversion.
+    void internalSetExtensionSet(FieldSet<FieldDescriptor> extensions) {
+      this.extensions = FieldSet.Builder.fromFieldSet(extensions);
+    }
+
+    @Override
+    public BuilderT clear() {
+      extensions = null;
+      return super.clear();
+    }
+
+    private void ensureExtensionsIsMutable() {
+      if (extensions == null) {
+        extensions = FieldSet.newBuilder();
+      }
+    }
+
+    private void verifyExtensionContainingType(final Extension<MessageT, ?> extension) {
+      if (extension.getDescriptor().getContainingType() != getDescriptorForType()) {
+        // This can only happen if someone uses unchecked operations.
+        throw new IllegalArgumentException(
+            "Extension is for type \""
+                + extension.getDescriptor().getContainingType().getFullName()
+                + "\" which does not match message type \""
+                + getDescriptorForType().getFullName()
+                + "\".");
+      }
+    }
+
+    /** Check if a singular extension is present. */
+    @Override
+    public final <T> boolean hasExtension(final ExtensionLite<MessageT, T> extensionLite) {
+      Extension<MessageT, T> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      return extensions != null && extensions.hasField(extension.getDescriptor());
+    }
+
+    /** Get the number of elements in a repeated extension. */
+    @Override
+    public final <T> int getExtensionCount(final ExtensionLite<MessageT, List<T>> extensionLite) {
+      Extension<MessageT, List<T>> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      final FieldDescriptor descriptor = extension.getDescriptor();
+      return extensions == null ? 0 : extensions.getRepeatedFieldCount(descriptor);
+    }
+
+    /** Get the value of an extension. */
+    @Override
+    public final <T> T getExtension(final ExtensionLite<MessageT, T> extensionLite) {
+      Extension<MessageT, T> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      FieldDescriptor descriptor = extension.getDescriptor();
+      final Object value = extensions == null ? null : extensions.getField(descriptor);
+      if (value == null) {
+        if (descriptor.isRepeated()) {
+          return (T) Collections.emptyList();
+        } else if (descriptor.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+          return (T) extension.getMessageDefaultInstance();
+        } else {
+          return (T) extension.fromReflectionType(descriptor.getDefaultValue());
+        }
+      } else {
+        return (T) extension.fromReflectionType(value);
+      }
+    }
+
+    /** Get one element of a repeated extension. */
+    @Override
+    public final <T> T getExtension(
+        final ExtensionLite<MessageT, List<T>> extensionLite, final int index) {
+      Extension<MessageT, List<T>> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      FieldDescriptor descriptor = extension.getDescriptor();
+      if (extensions == null) {
+        throw new IndexOutOfBoundsException();
+      }
+      return (T)
+          extension.singularFromReflectionType(extensions.getRepeatedField(descriptor, index));
+    }
+
+    /** Set the value of an extension. */
+    public final <T> BuilderT setExtension(
+        final ExtensionLite<MessageT, T> extensionLite, final T value) {
+      Extension<MessageT, T> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      ensureExtensionsIsMutable();
+      final FieldDescriptor descriptor = extension.getDescriptor();
+      extensions.setField(descriptor, extension.toReflectionType(value));
+      onChanged();
+      return (BuilderT) this;
+    }
+
+    /** Set the value of one element of a repeated extension. */
+    public final <T> BuilderT setExtension(
+        final ExtensionLite<MessageT, List<T>> extensionLite, final int index, final T value) {
+      Extension<MessageT, List<T>> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      ensureExtensionsIsMutable();
+      final FieldDescriptor descriptor = extension.getDescriptor();
+      extensions.setRepeatedField(descriptor, index, extension.singularToReflectionType(value));
+      onChanged();
+      return (BuilderT) this;
+    }
+
+    /** Append a value to a repeated extension. */
+    public final <T> BuilderT addExtension(
+        final ExtensionLite<MessageT, List<T>> extensionLite, final T value) {
+      Extension<MessageT, List<T>> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      ensureExtensionsIsMutable();
+      final FieldDescriptor descriptor = extension.getDescriptor();
+      extensions.addRepeatedField(descriptor, extension.singularToReflectionType(value));
+      onChanged();
+      return (BuilderT) this;
+    }
+
+    /** Clear an extension. */
+    public final <T> BuilderT clearExtension(final ExtensionLite<MessageT, T> extensionLite) {
+      Extension<MessageT, T> extension = checkNotLite(extensionLite);
+
+      verifyExtensionContainingType(extension);
+      ensureExtensionsIsMutable();
+      extensions.clearField(extension.getDescriptor());
+      onChanged();
+      return (BuilderT) this;
+    }
+
+    /**
+     * Check if a singular extension is present.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> boolean hasExtension(final Extension<MessageT, T> extension) {
+      return hasExtension((ExtensionLite<MessageT, T>) extension);
+    }
+    /**
+     * Check if a singular extension is present.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> boolean hasExtension(
+        final GeneratedExtension<MessageT, T> extension) {
+      return hasExtension((ExtensionLite<MessageT, T>) extension);
+    }
+    /**
+     * Get the number of elements in a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> int getExtensionCount(
+        final Extension<MessageT, List<T>> extension) {
+      return getExtensionCount((ExtensionLite<MessageT, List<T>>) extension);
+    }
+    /**
+     * Get the number of elements in a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> int getExtensionCount(
+        final GeneratedExtension<MessageT, List<T>> extension) {
+      return getExtensionCount((ExtensionLite<MessageT, List<T>>) extension);
+    }
+    /**
+     * Get the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> T getExtension(final Extension<MessageT, T> extension) {
+      return getExtension((ExtensionLite<MessageT, T>) extension);
+    }
+    /** Get the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> T getExtension(
+        final GeneratedExtension<MessageT, T> extension) {
+      return getExtension((ExtensionLite<MessageT, T>) extension);
+    }
+    /**
+     * Get the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> T getExtension(
+        final Extension<MessageT, List<T>> extension, final int index) {
+      return getExtension((ExtensionLite<MessageT, List<T>>) extension, index);
+    }
+    /**
+     * Get the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    @Override
+    public final <T> T getExtension(
+        final GeneratedExtension<MessageT, List<T>> extension, final int index) {
+      return getExtension((ExtensionLite<MessageT, List<T>>) extension, index);
+    }
+    /**
+     * Set the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    public final <T> BuilderT setExtension(
+        final Extension<MessageT, T> extension, final T value) {
+      return setExtension((ExtensionLite<MessageT, T>) extension, value);
+    }
+    /**
+     * Set the value of an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    public <T> BuilderT setExtension(
+        final GeneratedExtension<MessageT, T> extension, final T value) {
+      return setExtension((ExtensionLite<MessageT, T>) extension, value);
+    }
+    /**
+     * Set the value of one element of a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    public final <T> BuilderT setExtension(
+        final Extension<MessageT, List<T>> extension,
+        final int index, final T value) {
+      return setExtension((ExtensionLite<MessageT, List<T>>) extension, index, value);
+    }
+    /**
+     * Set the value of one element of a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    public <T> BuilderT setExtension(
+        final GeneratedExtension<MessageT, List<T>> extension,
+        final int index, final T value) {
+      return setExtension((ExtensionLite<MessageT, List<T>>) extension, index, value);
+    }
+    /**
+     * Append a value to a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    public final <T> BuilderT addExtension(
+        final Extension<MessageT, List<T>> extension, final T value) {
+      return addExtension((ExtensionLite<MessageT, List<T>>) extension, value);
+    }
+    /**
+     * Append a value to a repeated extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    public <T> BuilderT addExtension(
+        final GeneratedExtension<MessageT, List<T>> extension, final T value) {
+      return addExtension((ExtensionLite<MessageT, List<T>>) extension, value);
+    }
+    /**
+     * Clear an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    public final <T> BuilderT clearExtension(
+        final Extension<MessageT, T> extension) {
+      return clearExtension((ExtensionLite<MessageT, T>) extension);
+    }
+    /**
+     * Clears an extension.
+     * <p>TODO: handled by ExtensionLite version
+     */
+    public <T> BuilderT clearExtension(
+        final GeneratedExtension<MessageT, T> extension) {
+      return clearExtension((ExtensionLite<MessageT, T>) extension);
+    }
+
+    /** Called by subclasses to check if all extensions are initialized. */
+    protected boolean extensionsAreInitialized() {
+      return extensions == null || extensions.isInitialized();
+    }
+
+    /**
+     * Called by the build code path to create a copy of the extensions for building the message.
+     */
+    private FieldSet<FieldDescriptor> buildExtensions() {
+      return extensions == null
+          ? (FieldSet<FieldDescriptor>) FieldSet.emptySet()
+          : extensions.buildPartial();
+    }
+
+    @Override
+    public boolean isInitialized() {
+      return super.isInitialized() && extensionsAreInitialized();
+    }
+
+    // ---------------------------------------------------------------
+    // Reflection
+
+    @Override
+    public Map<FieldDescriptor, Object> getAllFields() {
+      final Map<FieldDescriptor, Object> result = super.getAllFieldsMutable();
+      if (extensions != null) {
+        result.putAll(extensions.getAllFields());
+      }
+      return Collections.unmodifiableMap(result);
+    }
+
+    @Override
+    public Object getField(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        final Object value = extensions == null ? null : extensions.getField(field);
+        if (value == null) {
+          if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+            // Lacking an ExtensionRegistry, we have no way to determine the
+            // extension's real type, so we return a DynamicMessage.
+            return DynamicMessage.getDefaultInstance(field.getMessageType());
+          } else {
+            return field.getDefaultValue();
+          }
+        } else {
+          return value;
+        }
+      } else {
+        return super.getField(field);
+      }
+    }
+
+    @Override
+    public Message.Builder getFieldBuilder(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        if (field.getJavaType() != FieldDescriptor.JavaType.MESSAGE) {
+          throw new UnsupportedOperationException(
+              "getFieldBuilder() called on a non-Message type.");
+        }
+        ensureExtensionsIsMutable();
+        final Object value = extensions.getFieldAllowBuilders(field);
+        if (value == null) {
+          Message.Builder builder = DynamicMessage.newBuilder(field.getMessageType());
+          extensions.setField(field, builder);
+          onChanged();
+          return builder;
+        } else {
+          if (value instanceof Message.Builder) {
+            return (Message.Builder) value;
+          } else if (value instanceof Message) {
+            Message.Builder builder = ((Message) value).toBuilder();
+            extensions.setField(field, builder);
+            onChanged();
+            return builder;
+          } else {
+            throw new UnsupportedOperationException(
+                "getRepeatedFieldBuilder() called on a non-Message type.");
+          }
+        }
+      } else {
+        return super.getFieldBuilder(field);
+      }
+    }
+
+    @Override
+    public int getRepeatedFieldCount(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        return extensions == null ? 0 : extensions.getRepeatedFieldCount(field);
+      } else {
+        return super.getRepeatedFieldCount(field);
+      }
+    }
+
+    @Override
+    public Object getRepeatedField(final FieldDescriptor field, final int index) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        if (extensions == null) {
+          throw new IndexOutOfBoundsException();
+        }
+        return extensions.getRepeatedField(field, index);
+      } else {
+        return super.getRepeatedField(field, index);
+      }
+    }
+
+    @Override
+    public Message.Builder getRepeatedFieldBuilder(final FieldDescriptor field, final int index) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        ensureExtensionsIsMutable();
+        if (field.getJavaType() != FieldDescriptor.JavaType.MESSAGE) {
+          throw new UnsupportedOperationException(
+              "getRepeatedFieldBuilder() called on a non-Message type.");
+        }
+        final Object value = extensions.getRepeatedFieldAllowBuilders(field, index);
+        if (value instanceof Message.Builder) {
+          return (Message.Builder) value;
+        } else if (value instanceof Message) {
+          Message.Builder builder = ((Message) value).toBuilder();
+          extensions.setRepeatedField(field, index, builder);
+          onChanged();
+          return builder;
+        } else {
+          throw new UnsupportedOperationException(
+              "getRepeatedFieldBuilder() called on a non-Message type.");
+        }
+      } else {
+        return super.getRepeatedFieldBuilder(field, index);
+      }
+    }
+
+    @Override
+    public boolean hasField(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        return extensions != null && extensions.hasField(field);
+      } else {
+        return super.hasField(field);
+      }
+    }
+
+    @Override
+    public BuilderT setField(final FieldDescriptor field, final Object value) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        ensureExtensionsIsMutable();
+        extensions.setField(field, value);
+        onChanged();
+        return (BuilderT) this;
+      } else {
+        return super.setField(field, value);
+      }
+    }
+
+    @Override
+    public BuilderT clearField(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        ensureExtensionsIsMutable();
+        extensions.clearField(field);
+        onChanged();
+        return (BuilderT) this;
+      } else {
+        return super.clearField(field);
+      }
+    }
+
+    @Override
+    public BuilderT setRepeatedField(
+        final FieldDescriptor field, final int index, final Object value) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        ensureExtensionsIsMutable();
+        extensions.setRepeatedField(field, index, value);
+        onChanged();
+        return (BuilderT) this;
+      } else {
+        return super.setRepeatedField(field, index, value);
+      }
+    }
+
+    @Override
+    public BuilderT addRepeatedField(final FieldDescriptor field, final Object value) {
+      if (field.isExtension()) {
+        verifyContainingType(field);
+        ensureExtensionsIsMutable();
+        extensions.addRepeatedField(field, value);
+        onChanged();
+        return (BuilderT) this;
+      } else {
+        return super.addRepeatedField(field, value);
+      }
+    }
+
+    @Override
+    public Message.Builder newBuilderForField(final FieldDescriptor field) {
+      if (field.isExtension()) {
+        return DynamicMessage.newBuilder(field.getMessageType());
+      } else {
+        return super.newBuilderForField(field);
+      }
+    }
+
+    protected final void mergeExtensionFields(final ExtendableMessage<?> other) {
+      if (other.extensions != null) {
+        ensureExtensionsIsMutable();
+        extensions.mergeFrom(other.extensions);
+        onChanged();
+      }
+    }
+
+    @Override
+    protected boolean parseUnknownField(
+        CodedInputStream input, ExtensionRegistryLite extensionRegistry, int tag)
+        throws IOException {
+      ensureExtensionsIsMutable();
+      return MessageReflection.mergeFieldFrom(
+          input,
+          input.shouldDiscardUnknownFields() ? null : getUnknownFieldSetBuilder(),
+          extensionRegistry,
+          getDescriptorForType(),
+          new MessageReflection.ExtensionBuilderAdapter(extensions),
+          tag);
+    }
+
+    private void verifyContainingType(final FieldDescriptor field) {
+      if (field.getContainingType() != getDescriptorForType()) {
+        throw new IllegalArgumentException("FieldDescriptor does not match message type.");
+      }
+    }
+  }
+
+  // -----------------------------------------------------------------
+
+  /**
+   * Gets the descriptor for an extension. The implementation depends on whether the extension is
+   * scoped in the top level of a file or scoped in a Message.
+   */
+  interface ExtensionDescriptorRetriever {
+    FieldDescriptor getDescriptor();
+  }
+
+  // =================================================================
+
+  /** Calls Class.getMethod and throws a RuntimeException if it fails. */
+  private static Method getMethodOrDie(
+      final Class<?> clazz, final String name, final Class<?>... params) {
+    try {
+      return clazz.getMethod(name, params);
+    } catch (NoSuchMethodException e) {
+      throw new IllegalStateException(
+          "Generated message class \"" + clazz.getName() + "\" missing method \"" + name + "\".",
+          e);
+    }
+  }
+
+  /** Calls invoke and throws a RuntimeException if it fails. */
+  @CanIgnoreReturnValue
+  private static Object invokeOrDie(
+      final Method method, final Object object, final Object... params) {
+    try {
+      return method.invoke(object, params);
+    } catch (IllegalAccessException e) {
+      throw new IllegalStateException(
+          "Couldn't use Java reflection to implement protocol message reflection.", e);
+    } catch (InvocationTargetException e) {
+      final Throwable cause = e.getCause();
+      if (cause instanceof RuntimeException) {
+        throw (RuntimeException) cause;
+      } else if (cause instanceof Error) {
+        throw (Error) cause;
+      } else {
+        throw new IllegalStateException(
+            "Unexpected exception thrown by generated accessor method.", cause);
+      }
+    }
+  }
+
+  /**
+   * Gets the map field with the given field number. This method should be overridden in the
+   * generated message class if the message contains map fields.
+   *
+   * <p>Unlike other field types, reflection support for map fields can't be implemented based on
+   * generated public API because we need to access a map field as a list in reflection API but the
+   * generated API only allows us to access it as a map. This method returns the underlying map
+   * field directly and thus enables us to access the map field as a list.
+   */
+  @SuppressWarnings("unused")
+  protected MapFieldReflectionAccessor internalGetMapFieldReflection(int fieldNumber) {
+    return internalGetMapField(fieldNumber);
+  }
+
+  /** TODO: Remove, exists for compatibility with generated code. */
+  @Deprecated
+  @SuppressWarnings({"rawtypes", "unused"})
+  protected MapField internalGetMapField(int fieldNumber) {
+    // Note that we can't use descriptor names here because this method will
+    // be called when descriptor is being initialized.
+    throw new IllegalArgumentException("No map fields found in " + getClass().getName());
+  }
+
+  /**
+   * Users should ignore this class. This class provides the implementation with access to the
+   * fields of a message object using Java reflection.
+   */
+  public static final class FieldAccessorTable {
+
+    /**
+     * Construct a FieldAccessorTable for a particular message class. Only one FieldAccessorTable
+     * should ever be constructed per class.
+     *
+     * @param descriptor The type's descriptor.
+     * @param camelCaseNames The camelcase names of all fields in the message. These are used to
+     *     derive the accessor method names.
+     * @param messageClass The message type.
+     * @param builderClass The builder type.
+     */
+    public FieldAccessorTable(
+        final Descriptor descriptor,
+        final String[] camelCaseNames,
+        final Class<? extends GeneratedMessageV3Internal> messageClass,
+        final Class<? extends Builder<?>> builderClass) {
+      this(descriptor, camelCaseNames);
+      ensureFieldAccessorsInitialized(messageClass, builderClass);
+    }
+
+    /**
+     * Construct a FieldAccessorTable for a particular message class without initializing
+     * FieldAccessors.
+     */
+    public FieldAccessorTable(final Descriptor descriptor, final String[] camelCaseNames) {
+      this.descriptor = descriptor;
+      this.camelCaseNames = camelCaseNames;
+      fields = new FieldAccessor[descriptor.getFields().size()];
+      oneofs = new OneofAccessor[descriptor.getOneofs().size()];
+      initialized = false;
+    }
+
+    /**
+     * Ensures the field accessors are initialized. This method is thread-safe.
+     *
+     * @param messageClass The message type.
+     * @param builderClass The builder type.
+     * @return this
+     */
+    public FieldAccessorTable ensureFieldAccessorsInitialized(
+        Class<? extends GeneratedMessageV3Internal> messageClass, Class<? extends Builder<?>> builderClass) {
+      if (initialized) {
+        return this;
+      }
+      synchronized (this) {
+        if (initialized) {
+          return this;
+        }
+        int fieldsSize = fields.length;
+        for (int i = 0; i < fieldsSize; i++) {
+          FieldDescriptor field = descriptor.getFields().get(i);
+          String containingOneofCamelCaseName = null;
+          if (field.getContainingOneof() != null) {
+            int index = fieldsSize + field.getContainingOneof().getIndex();
+            if (index < camelCaseNames.length) {
+              containingOneofCamelCaseName = camelCaseNames[index];
+            }
+          }
+          if (field.isRepeated()) {
+            if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+              if (field.isMapField()) {
+                fields[i] = new MapFieldAccessor(field, messageClass);
+              } else {
+                fields[i] =
+                    new RepeatedMessageFieldAccessor(
+                        field, camelCaseNames[i], messageClass, builderClass);
+              }
+            } else if (field.getJavaType() == FieldDescriptor.JavaType.ENUM) {
+              fields[i] =
+                  new RepeatedEnumFieldAccessor(
+                      field, camelCaseNames[i], messageClass, builderClass);
+            } else {
+              fields[i] =
+                  new RepeatedFieldAccessor(field, camelCaseNames[i], messageClass, builderClass);
+            }
+          } else {
+            if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+              fields[i] =
+                  new SingularMessageFieldAccessor(
+                      field,
+                      camelCaseNames[i],
+                      messageClass,
+                      builderClass,
+                      containingOneofCamelCaseName);
+            } else if (field.getJavaType() == FieldDescriptor.JavaType.ENUM) {
+              fields[i] =
+                  new SingularEnumFieldAccessor(
+                      field,
+                      camelCaseNames[i],
+                      messageClass,
+                      builderClass,
+                      containingOneofCamelCaseName);
+            } else if (field.getJavaType() == FieldDescriptor.JavaType.STRING) {
+              fields[i] =
+                  new SingularStringFieldAccessor(
+                      field,
+                      camelCaseNames[i],
+                      messageClass,
+                      builderClass,
+                      containingOneofCamelCaseName);
+            } else {
+              fields[i] =
+                  new SingularFieldAccessor(
+                      field,
+                      camelCaseNames[i],
+                      messageClass,
+                      builderClass,
+                      containingOneofCamelCaseName);
+            }
+          }
+        }
+
+        for (int i = 0; i < descriptor.getOneofs().size(); i++) {
+          if (i < descriptor.getRealOneofs().size()) {
+            oneofs[i] =
+                new RealOneofAccessor(
+                    descriptor, i, camelCaseNames[i + fieldsSize], messageClass, builderClass);
+          } else {
+            oneofs[i] = new SyntheticOneofAccessor(descriptor, i);
+          }
+        }
+
+        initialized = true;
+        camelCaseNames = null;
+        return this;
+      }
+    }
+
+    private final Descriptor descriptor;
+    private final FieldAccessor[] fields;
+    private String[] camelCaseNames;
+    private final OneofAccessor[] oneofs;
+    private volatile boolean initialized;
+
+    /** Get the FieldAccessor for a particular field. */
+    private FieldAccessor getField(final FieldDescriptor field) {
+      if (field.getContainingType() != descriptor) {
+        throw new IllegalArgumentException("FieldDescriptor does not match message type.");
+      } else if (field.isExtension()) {
+        // If this type had extensions, it would subclass ExtendableMessage,
+        // which overrides the reflection interface to handle extensions.
+        throw new IllegalArgumentException("This type does not have extensions.");
+      }
+      return fields[field.getIndex()];
+    }
+
+    /** Get the OneofAccessor for a particular oneof. */
+    private OneofAccessor getOneof(final OneofDescriptor oneof) {
+      if (oneof.getContainingType() != descriptor) {
+        throw new IllegalArgumentException("OneofDescriptor does not match message type.");
+      }
+      return oneofs[oneof.getIndex()];
+    }
+
+    /**
+     * Abstract interface that provides access to a single field. This is implemented differently
+     * depending on the field type and cardinality.
+     */
+    private interface FieldAccessor {
+      Object get(GeneratedMessageV3Internal message);
+
+      Object get(GeneratedMessageV3Internal.Builder<?> builder);
+
+      Object getRaw(GeneratedMessageV3Internal message);
+
+      void set(Builder<?> builder, Object value);
+
+      Object getRepeated(GeneratedMessageV3Internal message, int index);
+
+      Object getRepeated(GeneratedMessageV3Internal.Builder<?> builder, int index);
+
+      void setRepeated(Builder<?> builder, int index, Object value);
+
+      void addRepeated(Builder<?> builder, Object value);
+
+      boolean has(GeneratedMessageV3Internal message);
+
+      boolean has(GeneratedMessageV3Internal.Builder<?> builder);
+
+      int getRepeatedCount(GeneratedMessageV3Internal message);
+
+      int getRepeatedCount(GeneratedMessageV3Internal.Builder<?> builder);
+
+      void clear(Builder<?> builder);
+
+      Message.Builder newBuilder();
+
+      Message.Builder getBuilder(GeneratedMessageV3Internal.Builder<?> builder);
+
+      Message.Builder getRepeatedBuilder(GeneratedMessageV3Internal.Builder<?> builder, int index);
+    }
+
+    /** OneofAccessor provides access to a single oneof. */
+    private static interface OneofAccessor {
+      public boolean has(final GeneratedMessageV3Internal message);
+
+      public boolean has(GeneratedMessageV3Internal.Builder<?> builder);
+
+      public FieldDescriptor get(final GeneratedMessageV3Internal message);
+
+      public FieldDescriptor get(GeneratedMessageV3Internal.Builder<?> builder);
+
+      public void clear(final Builder<?> builder);
+    }
+
+    /** RealOneofAccessor provides access to a single real oneof. */
+    private static class RealOneofAccessor implements OneofAccessor {
+      RealOneofAccessor(
+          final Descriptor descriptor,
+          final int oneofIndex,
+          final String camelCaseName,
+          final Class<? extends GeneratedMessageV3Internal> messageClass,
+          final Class<? extends Builder<?>> builderClass) {
+        this.descriptor = descriptor;
+        caseMethod = getMethodOrDie(messageClass, "get" + camelCaseName + "Case");
+        caseMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName + "Case");
+        clearMethod = getMethodOrDie(builderClass, "clear" + camelCaseName);
+      }
+
+      private final Descriptor descriptor;
+      private final Method caseMethod;
+      private final Method caseMethodBuilder;
+      private final Method clearMethod;
+
+      @Override
+      public boolean has(final GeneratedMessageV3Internal message) {
+        return ((Internal.EnumLite) invokeOrDie(caseMethod, message)).getNumber() != 0;
+      }
+
+      @Override
+      public boolean has(GeneratedMessageV3Internal.Builder<?> builder) {
+        return ((Internal.EnumLite) invokeOrDie(caseMethodBuilder, builder)).getNumber() != 0;
+      }
+
+      @Override
+      public FieldDescriptor get(final GeneratedMessageV3Internal message) {
+        int fieldNumber = ((Internal.EnumLite) invokeOrDie(caseMethod, message)).getNumber();
+        if (fieldNumber > 0) {
+          return descriptor.findFieldByNumber(fieldNumber);
+        }
+        return null;
+      }
+
+      @Override
+      public FieldDescriptor get(GeneratedMessageV3Internal.Builder<?> builder) {
+        int fieldNumber = ((Internal.EnumLite) invokeOrDie(caseMethodBuilder, builder)).getNumber();
+        if (fieldNumber > 0) {
+          return descriptor.findFieldByNumber(fieldNumber);
+        }
+        return null;
+      }
+
+      @Override
+      public void clear(final Builder<?> builder) {
+        // TODO: remove the unused variable
+        Object unused = invokeOrDie(clearMethod, builder);
+      }
+    }
+
+    /** SyntheticOneofAccessor provides access to a single synthetic oneof. */
+    private static class SyntheticOneofAccessor implements OneofAccessor {
+      SyntheticOneofAccessor(final Descriptor descriptor, final int oneofIndex) {
+        OneofDescriptor oneofDescriptor = descriptor.getOneofs().get(oneofIndex);
+        fieldDescriptor = oneofDescriptor.getFields().get(0);
+      }
+
+      private final FieldDescriptor fieldDescriptor;
+
+      @Override
+      public boolean has(final GeneratedMessageV3Internal message) {
+        return message.hasField(fieldDescriptor);
+      }
+
+      @Override
+      public boolean has(GeneratedMessageV3Internal.Builder<?> builder) {
+        return builder.hasField(fieldDescriptor);
+      }
+
+      @Override
+      public FieldDescriptor get(final GeneratedMessageV3Internal message) {
+        return message.hasField(fieldDescriptor) ? fieldDescriptor : null;
+      }
+
+      public FieldDescriptor get(GeneratedMessageV3Internal.Builder<?> builder) {
+        return builder.hasField(fieldDescriptor) ? fieldDescriptor : null;
+      }
+
+      @Override
+      public void clear(final Builder<?> builder) {
+        builder.clearField(fieldDescriptor);
+      }
+    }
+
+    // ---------------------------------------------------------------
+
+    @SuppressWarnings("SameNameButDifferent")
+    private static class SingularFieldAccessor implements FieldAccessor {
+      private interface MethodInvoker {
+        Object get(final GeneratedMessageV3Internal message);
+
+        Object get(GeneratedMessageV3Internal.Builder<?> builder);
+
+        int getOneofFieldNumber(final GeneratedMessageV3Internal message);
+
+        int getOneofFieldNumber(final GeneratedMessageV3Internal.Builder<?> builder);
+
+        void set(final GeneratedMessageV3Internal.Builder<?> builder, final Object value);
+
+        boolean has(final GeneratedMessageV3Internal message);
+
+        boolean has(GeneratedMessageV3Internal.Builder<?> builder);
+
+        void clear(final GeneratedMessageV3Internal.Builder<?> builder);
+      }
+
+      private static final class ReflectionInvoker implements MethodInvoker {
+        private final Method getMethod;
+        private final Method getMethodBuilder;
+        private final Method setMethod;
+        private final Method hasMethod;
+        private final Method hasMethodBuilder;
+        private final Method clearMethod;
+        private final Method caseMethod;
+        private final Method caseMethodBuilder;
+
+        ReflectionInvoker(
+            final FieldDescriptor descriptor,
+            final String camelCaseName,
+            final Class<? extends GeneratedMessageV3Internal> messageClass,
+            final Class<? extends Builder<?>> builderClass,
+            final String containingOneofCamelCaseName,
+            boolean isOneofField,
+            boolean hasHasMethod) {
+          getMethod = getMethodOrDie(messageClass, "get" + camelCaseName);
+          getMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName);
+          Class<?> type = getMethod.getReturnType();
+          setMethod = getMethodOrDie(builderClass, "set" + camelCaseName, type);
+          hasMethod = hasHasMethod ? getMethodOrDie(messageClass, "has" + camelCaseName) : null;
+          hasMethodBuilder =
+              hasHasMethod ? getMethodOrDie(builderClass, "has" + camelCaseName) : null;
+          clearMethod = getMethodOrDie(builderClass, "clear" + camelCaseName);
+          caseMethod =
+              isOneofField
+                  ? getMethodOrDie(messageClass, "get" + containingOneofCamelCaseName + "Case")
+                  : null;
+          caseMethodBuilder =
+              isOneofField
+                  ? getMethodOrDie(builderClass, "get" + containingOneofCamelCaseName + "Case")
+                  : null;
+        }
+
+        @Override
+        public Object get(final GeneratedMessageV3Internal message) {
+          return invokeOrDie(getMethod, message);
+        }
+
+        @Override
+        public Object get(GeneratedMessageV3Internal.Builder<?> builder) {
+          return invokeOrDie(getMethodBuilder, builder);
+        }
+
+        @Override
+        public int getOneofFieldNumber(final GeneratedMessageV3Internal message) {
+          return ((Internal.EnumLite) invokeOrDie(caseMethod, message)).getNumber();
+        }
+
+        @Override
+        public int getOneofFieldNumber(final GeneratedMessageV3Internal.Builder<?> builder) {
+          return ((Internal.EnumLite) invokeOrDie(caseMethodBuilder, builder)).getNumber();
+        }
+
+        @Override
+        public void set(final GeneratedMessageV3Internal.Builder<?> builder, final Object value) {
+          // TODO: remove the unused variable
+          Object unused = invokeOrDie(setMethod, builder, value);
+        }
+
+        @Override
+        public boolean has(final GeneratedMessageV3Internal message) {
+          return (Boolean) invokeOrDie(hasMethod, message);
+        }
+
+        @Override
+        public boolean has(GeneratedMessageV3Internal.Builder<?> builder) {
+          return (Boolean) invokeOrDie(hasMethodBuilder, builder);
+        }
+
+        @Override
+        public void clear(final GeneratedMessageV3Internal.Builder<?> builder) {
+          // TODO: remove the unused variable
+          Object unused = invokeOrDie(clearMethod, builder);
+        }
+      }
+
+      SingularFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends GeneratedMessageV3Internal> messageClass,
+          final Class<? extends Builder<?>> builderClass,
+          final String containingOneofCamelCaseName) {
+        isOneofField =
+            descriptor.getRealContainingOneof() != null;
+        hasHasMethod =
+            descriptor.getFile().getSyntax() == FileDescriptor.Syntax.EDITIONS && descriptor.hasPresence()
+                || descriptor.getFile().getSyntax() == FileDescriptor.Syntax.PROTO2
+                || descriptor.hasOptionalKeyword()
+                || (!isOneofField && descriptor.getJavaType() == FieldDescriptor.JavaType.MESSAGE);
+        ReflectionInvoker reflectionInvoker =
+            new ReflectionInvoker(
+                descriptor,
+                camelCaseName,
+                messageClass,
+                builderClass,
+                containingOneofCamelCaseName,
+                isOneofField,
+                hasHasMethod);
+        field = descriptor;
+        type = reflectionInvoker.getMethod.getReturnType();
+        invoker = getMethodInvoker(reflectionInvoker);
+      }
+
+      static MethodInvoker getMethodInvoker(ReflectionInvoker accessor) {
+        return accessor;
+      }
+
+      // Note:  We use Java reflection to call public methods rather than
+      //   access private fields directly as this avoids runtime security
+      //   checks.
+      protected final Class<?> type;
+      protected final FieldDescriptor field;
+      protected final boolean isOneofField;
+      protected final boolean hasHasMethod;
+      protected final MethodInvoker invoker;
+
+      @Override
+      public Object get(final GeneratedMessageV3Internal message) {
+        return invoker.get(message);
+      }
+
+      @Override
+      public Object get(GeneratedMessageV3Internal.Builder<?> builder) {
+        return invoker.get(builder);
+      }
+
+      @Override
+      public Object getRaw(final GeneratedMessageV3Internal message) {
+        return get(message);
+      }
+
+      @Override
+      public void set(final Builder<?> builder, final Object value) {
+        invoker.set(builder, value);
+      }
+
+      @Override
+      public Object getRepeated(final GeneratedMessageV3Internal message, final int index) {
+        throw new UnsupportedOperationException("getRepeatedField() called on a singular field.");
+      }
+
+      @Override
+      public Object getRepeated(GeneratedMessageV3Internal.Builder<?> builder, int index) {
+        throw new UnsupportedOperationException("getRepeatedField() called on a singular field.");
+      }
+
+      @Override
+      public void setRepeated(final Builder<?> builder, final int index, final Object value) {
+        throw new UnsupportedOperationException("setRepeatedField() called on a singular field.");
+      }
+
+      @Override
+      public void addRepeated(final Builder<?> builder, final Object value) {
+        throw new UnsupportedOperationException("addRepeatedField() called on a singular field.");
+      }
+
+      @Override
+      public boolean has(final GeneratedMessageV3Internal message) {
+        if (!hasHasMethod) {
+          if (isOneofField) {
+            return invoker.getOneofFieldNumber(message) == field.getNumber();
+          }
+          return !get(message).equals(field.getDefaultValue());
+        }
+        return invoker.has(message);
+      }
+
+      @Override
+      public boolean has(GeneratedMessageV3Internal.Builder<?> builder) {
+        if (!hasHasMethod) {
+          if (isOneofField) {
+            return invoker.getOneofFieldNumber(builder) == field.getNumber();
+          }
+          return !get(builder).equals(field.getDefaultValue());
+        }
+        return invoker.has(builder);
+      }
+
+      @Override
+      public int getRepeatedCount(final GeneratedMessageV3Internal message) {
+        throw new UnsupportedOperationException(
+            "getRepeatedFieldSize() called on a singular field.");
+      }
+
+      @Override
+      public int getRepeatedCount(GeneratedMessageV3Internal.Builder<?> builder) {
+        throw new UnsupportedOperationException(
+            "getRepeatedFieldSize() called on a singular field.");
+      }
+
+      @Override
+      public void clear(final Builder<?> builder) {
+        invoker.clear(builder);
+      }
+
+      @Override
+      public Message.Builder newBuilder() {
+        throw new UnsupportedOperationException(
+            "newBuilderForField() called on a non-Message type.");
+      }
+
+      @Override
+      public Message.Builder getBuilder(GeneratedMessageV3Internal.Builder<?> builder) {
+        throw new UnsupportedOperationException("getFieldBuilder() called on a non-Message type.");
+      }
+
+      @Override
+      public Message.Builder getRepeatedBuilder(GeneratedMessageV3Internal.Builder<?> builder, int index) {
+        throw new UnsupportedOperationException(
+            "getRepeatedFieldBuilder() called on a non-Message type.");
+      }
+    }
+
+    @SuppressWarnings("SameNameButDifferent")
+    private static class RepeatedFieldAccessor implements FieldAccessor {
+      interface MethodInvoker {
+        Object get(final GeneratedMessageV3Internal message);
+
+        Object get(GeneratedMessageV3Internal.Builder<?> builder);
+
+        Object getRepeated(final GeneratedMessageV3Internal message, final int index);
+
+        Object getRepeated(GeneratedMessageV3Internal.Builder<?> builder, int index);
+
+        void setRepeated(
+            final GeneratedMessageV3Internal.Builder<?> builder, final int index, final Object value);
+
+        void addRepeated(final GeneratedMessageV3Internal.Builder<?> builder, final Object value);
+
+        int getRepeatedCount(final GeneratedMessageV3Internal message);
+
+        int getRepeatedCount(GeneratedMessageV3Internal.Builder<?> builder);
+
+        void clear(final GeneratedMessageV3Internal.Builder<?> builder);
+      }
+
+      private static final class ReflectionInvoker implements MethodInvoker {
+        private final Method getMethod;
+        private final Method getMethodBuilder;
+        private final Method getRepeatedMethod;
+        private final Method getRepeatedMethodBuilder;
+        private final Method setRepeatedMethod;
+        private final Method addRepeatedMethod;
+        private final Method getCountMethod;
+        private final Method getCountMethodBuilder;
+        private final Method clearMethod;
+
+        ReflectionInvoker(
+            final FieldDescriptor descriptor,
+            final String camelCaseName,
+            final Class<? extends GeneratedMessageV3Internal> messageClass,
+            final Class<? extends Builder<?>> builderClass) {
+          getMethod = getMethodOrDie(messageClass, "get" + camelCaseName + "List");
+          getMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName + "List");
+          getRepeatedMethod = getMethodOrDie(messageClass, "get" + camelCaseName, Integer.TYPE);
+          getRepeatedMethodBuilder =
+              getMethodOrDie(builderClass, "get" + camelCaseName, Integer.TYPE);
+          Class<?> type = getRepeatedMethod.getReturnType();
+          setRepeatedMethod =
+              getMethodOrDie(builderClass, "set" + camelCaseName, Integer.TYPE, type);
+          addRepeatedMethod = getMethodOrDie(builderClass, "add" + camelCaseName, type);
+          getCountMethod = getMethodOrDie(messageClass, "get" + camelCaseName + "Count");
+          getCountMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName + "Count");
+          clearMethod = getMethodOrDie(builderClass, "clear" + camelCaseName);
+        }
+
+        @Override
+        public Object get(final GeneratedMessageV3Internal message) {
+          return invokeOrDie(getMethod, message);
+        }
+
+        @Override
+        public Object get(GeneratedMessageV3Internal.Builder<?> builder) {
+          return invokeOrDie(getMethodBuilder, builder);
+        }
+
+        @Override
+        public Object getRepeated(final GeneratedMessageV3Internal message, final int index) {
+          return invokeOrDie(getRepeatedMethod, message, index);
+        }
+
+        @Override
+        public Object getRepeated(GeneratedMessageV3Internal.Builder<?> builder, int index) {
+          return invokeOrDie(getRepeatedMethodBuilder, builder, index);
+        }
+
+        @Override
+        public void setRepeated(
+            final GeneratedMessageV3Internal.Builder<?> builder, final int index, final Object value) {
+          // TODO: remove the unused variable
+          Object unused = invokeOrDie(setRepeatedMethod, builder, index, value);
+        }
+
+        @Override
+        public void addRepeated(final GeneratedMessageV3Internal.Builder<?> builder, final Object value) {
+          // TODO: remove the unused variable
+          Object unused = invokeOrDie(addRepeatedMethod, builder, value);
+        }
+
+        @Override
+        public int getRepeatedCount(final GeneratedMessageV3Internal message) {
+          return (Integer) invokeOrDie(getCountMethod, message);
+        }
+
+        @Override
+        public int getRepeatedCount(GeneratedMessageV3Internal.Builder<?> builder) {
+          return (Integer) invokeOrDie(getCountMethodBuilder, builder);
+        }
+
+        @Override
+        public void clear(final GeneratedMessageV3Internal.Builder<?> builder) {
+          // TODO: remove the unused variable
+          Object unused = invokeOrDie(clearMethod, builder);
+        }
+      }
+
+      protected final Class<?> type;
+      protected final MethodInvoker invoker;
+
+      RepeatedFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends GeneratedMessageV3Internal> messageClass,
+          final Class<? extends Builder<?>> builderClass) {
+        ReflectionInvoker reflectionInvoker =
+            new ReflectionInvoker(descriptor, camelCaseName, messageClass, builderClass);
+        type = reflectionInvoker.getRepeatedMethod.getReturnType();
+        invoker = getMethodInvoker(reflectionInvoker);
+      }
+
+      static MethodInvoker getMethodInvoker(ReflectionInvoker accessor) {
+        return accessor;
+      }
+
+      @Override
+      public Object get(final GeneratedMessageV3Internal message) {
+        return invoker.get(message);
+      }
+
+      @Override
+      public Object get(GeneratedMessageV3Internal.Builder<?> builder) {
+        return invoker.get(builder);
+      }
+
+      @Override
+      public Object getRaw(final GeneratedMessageV3Internal message) {
+        return get(message);
+      }
+
+      @Override
+      public void set(final Builder<?> builder, final Object value) {
+        // Add all the elements individually.  This serves two purposes:
+        // 1) Verifies that each element has the correct type.
+        // 2) Insures that the caller cannot modify the list later on and
+        //    have the modifications be reflected in the message.
+        clear(builder);
+        for (final Object element : (List<?>) value) {
+          addRepeated(builder, element);
+        }
+      }
+
+      @Override
+      public Object getRepeated(final GeneratedMessageV3Internal message, final int index) {
+        return invoker.getRepeated(message, index);
+      }
+
+      @Override
+      public Object getRepeated(GeneratedMessageV3Internal.Builder<?> builder, int index) {
+        return invoker.getRepeated(builder, index);
+      }
+
+      @Override
+      public void setRepeated(final Builder<?> builder, final int index, final Object value) {
+        invoker.setRepeated(builder, index, value);
+      }
+
+      @Override
+      public void addRepeated(final Builder<?> builder, final Object value) {
+        invoker.addRepeated(builder, value);
+      }
+
+      @Override
+      public boolean has(final GeneratedMessageV3Internal message) {
+        throw new UnsupportedOperationException("hasField() called on a repeated field.");
+      }
+
+      @Override
+      public boolean has(GeneratedMessageV3Internal.Builder<?> builder) {
+        throw new UnsupportedOperationException("hasField() called on a repeated field.");
+      }
+
+      @Override
+      public int getRepeatedCount(final GeneratedMessageV3Internal message) {
+        return invoker.getRepeatedCount(message);
+      }
+
+      @Override
+      public int getRepeatedCount(GeneratedMessageV3Internal.Builder<?> builder) {
+        return invoker.getRepeatedCount(builder);
+      }
+
+      @Override
+      public void clear(final Builder<?> builder) {
+        invoker.clear(builder);
+      }
+
+      @Override
+      public Message.Builder newBuilder() {
+        throw new UnsupportedOperationException(
+            "newBuilderForField() called on a non-Message type.");
+      }
+
+      @Override
+      public Message.Builder getBuilder(GeneratedMessageV3Internal.Builder<?> builder) {
+        throw new UnsupportedOperationException("getFieldBuilder() called on a non-Message type.");
+      }
+
+      @Override
+      public Message.Builder getRepeatedBuilder(GeneratedMessageV3Internal.Builder<?> builder, int index) {
+        throw new UnsupportedOperationException(
+            "getRepeatedFieldBuilder() called on a non-Message type.");
+      }
+    }
+
+    private static class MapFieldAccessor implements FieldAccessor {
+      MapFieldAccessor(
+          final FieldDescriptor descriptor, final Class<? extends GeneratedMessageV3Internal> messageClass) {
+        field = descriptor;
+        Method getDefaultInstanceMethod = getMethodOrDie(messageClass, "getDefaultInstance");
+        MapFieldReflectionAccessor defaultMapField =
+            getMapField((GeneratedMessageV3Internal) invokeOrDie(getDefaultInstanceMethod, null));
+        mapEntryMessageDefaultInstance = defaultMapField.getMapEntryMessageDefaultInstance();
+      }
+
+      private final FieldDescriptor field;
+      private final Message mapEntryMessageDefaultInstance;
+
+      private MapFieldReflectionAccessor getMapField(GeneratedMessageV3Internal message) {
+        return message.internalGetMapFieldReflection(field.getNumber());
+      }
+
+      private MapFieldReflectionAccessor getMapField(GeneratedMessageV3Internal.Builder<?> builder) {
+        return builder.internalGetMapFieldReflection(field.getNumber());
+      }
+
+      private MapFieldReflectionAccessor getMutableMapField(GeneratedMessageV3Internal.Builder<?> builder) {
+        return builder.internalGetMutableMapFieldReflection(field.getNumber());
+      }
+
+      private Message coerceType(Message value) {
+        if (value == null) {
+          return null;
+        }
+        if (mapEntryMessageDefaultInstance.getClass().isInstance(value)) {
+          return value;
+        }
+        // The value is not the exact right message type.  However, if it
+        // is an alternative implementation of the same type -- e.g. a
+        // DynamicMessage -- we should accept it.  In this case we can make
+        // a copy of the message.
+        return mapEntryMessageDefaultInstance.toBuilder().mergeFrom(value).build();
+      }
+
+      @Override
+      public Object get(GeneratedMessageV3Internal message) {
+        List<Object> result = new ArrayList<>();
+        for (int i = 0; i < getRepeatedCount(message); i++) {
+          result.add(getRepeated(message, i));
+        }
+        return Collections.unmodifiableList(result);
+      }
+
+      @Override
+      public Object get(Builder<?> builder) {
+        List<Object> result = new ArrayList<>();
+        for (int i = 0; i < getRepeatedCount(builder); i++) {
+          result.add(getRepeated(builder, i));
+        }
+        return Collections.unmodifiableList(result);
+      }
+
+      @Override
+      public Object getRaw(GeneratedMessageV3Internal message) {
+        return get(message);
+      }
+
+      @Override
+      public void set(Builder<?> builder, Object value) {
+        clear(builder);
+        for (Object entry : (List<?>) value) {
+          addRepeated(builder, entry);
+        }
+      }
+
+      @Override
+      public Object getRepeated(GeneratedMessageV3Internal message, int index) {
+        return getMapField(message).getList().get(index);
+      }
+
+      @Override
+      public Object getRepeated(Builder<?> builder, int index) {
+        return getMapField(builder).getList().get(index);
+      }
+
+      @Override
+      public void setRepeated(Builder<?> builder, int index, Object value) {
+        getMutableMapField(builder).getMutableList().set(index, coerceType((Message) value));
+      }
+
+      @Override
+      public void addRepeated(Builder<?> builder, Object value) {
+        getMutableMapField(builder).getMutableList().add(coerceType((Message) value));
+      }
+
+      @Override
+      public boolean has(GeneratedMessageV3Internal message) {
+        throw new UnsupportedOperationException("hasField() is not supported for repeated fields.");
+      }
+
+      @Override
+      public boolean has(Builder<?> builder) {
+        throw new UnsupportedOperationException("hasField() is not supported for repeated fields.");
+      }
+
+      @Override
+      public int getRepeatedCount(GeneratedMessageV3Internal message) {
+        return getMapField(message).getList().size();
+      }
+
+      @Override
+      public int getRepeatedCount(Builder<?> builder) {
+        return getMapField(builder).getList().size();
+      }
+
+      @Override
+      public void clear(Builder<?> builder) {
+        getMutableMapField(builder).getMutableList().clear();
+      }
+
+      @Override
+      public Message.Builder newBuilder() {
+        return mapEntryMessageDefaultInstance.newBuilderForType();
+      }
+
+      @Override
+      public Message.Builder getBuilder(Builder<?> builder) {
+        throw new UnsupportedOperationException("Nested builder not supported for map fields.");
+      }
+
+      @Override
+      public Message.Builder getRepeatedBuilder(Builder<?> builder, int index) {
+        throw new UnsupportedOperationException("Map fields cannot be repeated");
+      }
+    }
+
+    // ---------------------------------------------------------------
+
+    private static final class SingularEnumFieldAccessor extends SingularFieldAccessor {
+      SingularEnumFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends GeneratedMessageV3Internal> messageClass,
+          final Class<? extends Builder<?>> builderClass,
+          final String containingOneofCamelCaseName) {
+        super(descriptor, camelCaseName, messageClass, builderClass, containingOneofCamelCaseName);
+
+        enumDescriptor = descriptor.getEnumType();
+
+        valueOfMethod = getMethodOrDie(type, "valueOf", EnumValueDescriptor.class);
+        getValueDescriptorMethod = getMethodOrDie(type, "getValueDescriptor");
+
+        supportUnknownEnumValue = !descriptor.legacyEnumFieldTreatedAsClosed();
+        if (supportUnknownEnumValue) {
+          getValueMethod = getMethodOrDie(messageClass, "get" + camelCaseName + "Value");
+          getValueMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName + "Value");
+          setValueMethod = getMethodOrDie(builderClass, "set" + camelCaseName + "Value", int.class);
+        }
+      }
+
+      private final EnumDescriptor enumDescriptor;
+
+      private final Method valueOfMethod;
+      private final Method getValueDescriptorMethod;
+
+      private final boolean supportUnknownEnumValue;
+      private Method getValueMethod;
+      private Method getValueMethodBuilder;
+      private Method setValueMethod;
+
+      @Override
+      public Object get(final GeneratedMessageV3Internal message) {
+        if (supportUnknownEnumValue) {
+          int value = (Integer) invokeOrDie(getValueMethod, message);
+          return enumDescriptor.findValueByNumberCreatingIfUnknown(value);
+        }
+        return invokeOrDie(getValueDescriptorMethod, super.get(message));
+      }
+
+      @Override
+      public Object get(final GeneratedMessageV3Internal.Builder<?> builder) {
+        if (supportUnknownEnumValue) {
+          int value = (Integer) invokeOrDie(getValueMethodBuilder, builder);
+          return enumDescriptor.findValueByNumberCreatingIfUnknown(value);
+        }
+        return invokeOrDie(getValueDescriptorMethod, super.get(builder));
+      }
+
+      @Override
+      public void set(final Builder<?> builder, final Object value) {
+        if (supportUnknownEnumValue) {
+          // TODO: remove the unused variable
+          Object unused =
+              invokeOrDie(setValueMethod, builder, ((EnumValueDescriptor) value).getNumber());
+          return;
+        }
+        super.set(builder, invokeOrDie(valueOfMethod, null, value));
+      }
+    }
+
+    private static final class RepeatedEnumFieldAccessor extends RepeatedFieldAccessor {
+      RepeatedEnumFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends GeneratedMessageV3Internal> messageClass,
+          final Class<? extends Builder<?>> builderClass) {
+        super(descriptor, camelCaseName, messageClass, builderClass);
+
+        enumDescriptor = descriptor.getEnumType();
+
+        valueOfMethod = getMethodOrDie(type, "valueOf", EnumValueDescriptor.class);
+        getValueDescriptorMethod = getMethodOrDie(type, "getValueDescriptor");
+
+        supportUnknownEnumValue = !descriptor.legacyEnumFieldTreatedAsClosed();
+        if (supportUnknownEnumValue) {
+          getRepeatedValueMethod =
+              getMethodOrDie(messageClass, "get" + camelCaseName + "Value", int.class);
+          getRepeatedValueMethodBuilder =
+              getMethodOrDie(builderClass, "get" + camelCaseName + "Value", int.class);
+          setRepeatedValueMethod =
+              getMethodOrDie(builderClass, "set" + camelCaseName + "Value", int.class, int.class);
+          addRepeatedValueMethod =
+              getMethodOrDie(builderClass, "add" + camelCaseName + "Value", int.class);
+        }
+      }
+
+      private final EnumDescriptor enumDescriptor;
+
+      private final Method valueOfMethod;
+      private final Method getValueDescriptorMethod;
+
+      private final boolean supportUnknownEnumValue;
+
+      private Method getRepeatedValueMethod;
+      private Method getRepeatedValueMethodBuilder;
+      private Method setRepeatedValueMethod;
+      private Method addRepeatedValueMethod;
+
+      @Override
+      public Object get(final GeneratedMessageV3Internal message) {
+        final List<Object> newList = new ArrayList<>();
+        final int size = getRepeatedCount(message);
+        for (int i = 0; i < size; i++) {
+          newList.add(getRepeated(message, i));
+        }
+        return Collections.unmodifiableList(newList);
+      }
+
+      @Override
+      public Object get(final GeneratedMessageV3Internal.Builder<?> builder) {
+        final List<Object> newList = new ArrayList<>();
+        final int size = getRepeatedCount(builder);
+        for (int i = 0; i < size; i++) {
+          newList.add(getRepeated(builder, i));
+        }
+        return Collections.unmodifiableList(newList);
+      }
+
+      @Override
+      public Object getRepeated(final GeneratedMessageV3Internal message, final int index) {
+        if (supportUnknownEnumValue) {
+          int value = (Integer) invokeOrDie(getRepeatedValueMethod, message, index);
+          return enumDescriptor.findValueByNumberCreatingIfUnknown(value);
+        }
+        return invokeOrDie(getValueDescriptorMethod, super.getRepeated(message, index));
+      }
+
+      @Override
+      public Object getRepeated(final GeneratedMessageV3Internal.Builder<?> builder, final int index) {
+        if (supportUnknownEnumValue) {
+          int value = (Integer) invokeOrDie(getRepeatedValueMethodBuilder, builder, index);
+          return enumDescriptor.findValueByNumberCreatingIfUnknown(value);
+        }
+        return invokeOrDie(getValueDescriptorMethod, super.getRepeated(builder, index));
+      }
+
+      @Override
+      public void setRepeated(final Builder<?> builder, final int index, final Object value) {
+        if (supportUnknownEnumValue) {
+          // TODO: remove the unused variable
+          Object unused =
+              invokeOrDie(
+                  setRepeatedValueMethod,
+                  builder,
+                  index,
+                  ((EnumValueDescriptor) value).getNumber());
+          return;
+        }
+        super.setRepeated(builder, index, invokeOrDie(valueOfMethod, null, value));
+      }
+
+      @Override
+      public void addRepeated(final Builder<?> builder, final Object value) {
+        if (supportUnknownEnumValue) {
+          // TODO: remove the unused variable
+          Object unused =
+              invokeOrDie(
+                  addRepeatedValueMethod, builder, ((EnumValueDescriptor) value).getNumber());
+          return;
+        }
+        super.addRepeated(builder, invokeOrDie(valueOfMethod, null, value));
+      }
+    }
+
+    // ---------------------------------------------------------------
+
+    /**
+     * Field accessor for string fields.
+     *
+     * <p>This class makes getFooBytes() and setFooBytes() available for reflection API so that
+     * reflection based serialize/parse functions can access the raw bytes of the field to preserve
+     * non-UTF8 bytes in the string.
+     *
+     * <p>This ensures the serialize/parse round-trip safety, which is important for servers which
+     * forward messages.
+     */
+    private static final class SingularStringFieldAccessor extends SingularFieldAccessor {
+      SingularStringFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends GeneratedMessageV3Internal> messageClass,
+          final Class<? extends Builder<?>> builderClass,
+          final String containingOneofCamelCaseName) {
+        super(descriptor, camelCaseName, messageClass, builderClass, containingOneofCamelCaseName);
+        getBytesMethod = getMethodOrDie(messageClass, "get" + camelCaseName + "Bytes");
+        setBytesMethodBuilder =
+            getMethodOrDie(builderClass, "set" + camelCaseName + "Bytes", ByteString.class);
+      }
+
+      private final Method getBytesMethod;
+      private final Method setBytesMethodBuilder;
+
+      @Override
+      public Object getRaw(final GeneratedMessageV3Internal message) {
+        return invokeOrDie(getBytesMethod, message);
+      }
+
+      @Override
+      public void set(GeneratedMessageV3Internal.Builder<?> builder, Object value) {
+        if (value instanceof ByteString) {
+          // TODO: remove the unused variable
+          Object unused = invokeOrDie(setBytesMethodBuilder, builder, value);
+        } else {
+          super.set(builder, value);
+        }
+      }
+    }
+
+    // ---------------------------------------------------------------
+
+    private static final class SingularMessageFieldAccessor extends SingularFieldAccessor {
+      SingularMessageFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends GeneratedMessageV3Internal> messageClass,
+          final Class<? extends Builder<?>> builderClass,
+          final String containingOneofCamelCaseName) {
+        super(descriptor, camelCaseName, messageClass, builderClass, containingOneofCamelCaseName);
+
+        newBuilderMethod = getMethodOrDie(type, "newBuilder");
+        getBuilderMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName + "Builder");
+      }
+
+      private final Method newBuilderMethod;
+      private final Method getBuilderMethodBuilder;
+
+      private Object coerceType(final Object value) {
+        if (type.isInstance(value)) {
+          return value;
+        } else {
+          // The value is not the exact right message type.  However, if it
+          // is an alternative implementation of the same type -- e.g. a
+          // DynamicMessage -- we should accept it.  In this case we can make
+          // a copy of the message.
+          return ((Message.Builder) invokeOrDie(newBuilderMethod, null))
+              .mergeFrom((Message) value)
+              .buildPartial();
+        }
+      }
+
+      @Override
+      public void set(final Builder<?> builder, final Object value) {
+        super.set(builder, coerceType(value));
+      }
+
+      @Override
+      public Message.Builder newBuilder() {
+        return (Message.Builder) invokeOrDie(newBuilderMethod, null);
+      }
+
+      @Override
+      public Message.Builder getBuilder(GeneratedMessageV3Internal.Builder<?> builder) {
+        return (Message.Builder) invokeOrDie(getBuilderMethodBuilder, builder);
+      }
+    }
+
+    private static final class RepeatedMessageFieldAccessor extends RepeatedFieldAccessor {
+      RepeatedMessageFieldAccessor(
+          final FieldDescriptor descriptor,
+          final String camelCaseName,
+          final Class<? extends GeneratedMessageV3Internal> messageClass,
+          final Class<? extends Builder<?>> builderClass) {
+        super(descriptor, camelCaseName, messageClass, builderClass);
+
+        newBuilderMethod = getMethodOrDie(type, "newBuilder");
+        getBuilderMethodBuilder =
+            getMethodOrDie(builderClass, "get" + camelCaseName + "Builder", Integer.TYPE);
+      }
+
+      private final Method newBuilderMethod;
+      private final Method getBuilderMethodBuilder;
+
+      private Object coerceType(final Object value) {
+        if (type.isInstance(value)) {
+          return value;
+        } else {
+          // The value is not the exact right message type.  However, if it
+          // is an alternative implementation of the same type -- e.g. a
+          // DynamicMessage -- we should accept it.  In this case we can make
+          // a copy of the message.
+          return ((Message.Builder) invokeOrDie(newBuilderMethod, null))
+              .mergeFrom((Message) value)
+              .build();
+        }
+      }
+
+      @Override
+      public void setRepeated(final Builder<?> builder, final int index, final Object value) {
+        super.setRepeated(builder, index, coerceType(value));
+      }
+
+      @Override
+      public void addRepeated(final Builder<?> builder, final Object value) {
+        super.addRepeated(builder, coerceType(value));
+      }
+
+      @Override
+      public Message.Builder newBuilder() {
+        return (Message.Builder) invokeOrDie(newBuilderMethod, null);
+      }
+
+      @Override
+      public Message.Builder getRepeatedBuilder(
+          final GeneratedMessageV3Internal.Builder<?> builder, final int index) {
+        return (Message.Builder) invokeOrDie(getBuilderMethodBuilder, builder, index);
+      }
+    }
+  }
+
+  /**
+   * Replaces this object in the output stream with a serialized form. Part of Java's serialization
+   * magic. Generated sub-classes must override this method by calling {@code return
+   * super.writeReplace();}
+   *
+   * @return a SerializedForm of this message
+   */
+  protected Object writeReplace() throws ObjectStreamException {
+    return new SerializedForm(this);
+  }
+
+  /**
+   * Checks that the {@link Extension} is non-Lite and returns it as a {@link GeneratedExtension}.
+   */
+  private static <MessageT extends ExtendableMessage<MessageT>, T>
+      Extension<MessageT, T> checkNotLite(ExtensionLite<MessageT, T> extension) {
+    if (extension.isLite()) {
+      throw new IllegalArgumentException("Expected non-lite extension.");
+    }
+
+    return (Extension<MessageT, T>) extension;
+  }
+
+  protected static boolean isStringEmpty(final Object value) {
+    if (value instanceof String) {
+      return ((String) value).isEmpty();
+    } else {
+      return ((ByteString) value).isEmpty();
+    }
+  }
+
+  protected static int computeStringSize(final int fieldNumber, final Object value) {
+    if (value instanceof String) {
+      return CodedOutputStream.computeStringSize(fieldNumber, (String) value);
+    } else {
+      return CodedOutputStream.computeBytesSize(fieldNumber, (ByteString) value);
+    }
+  }
+
+  protected static int computeStringSizeNoTag(final Object value) {
+    if (value instanceof String) {
+      return CodedOutputStream.computeStringSizeNoTag((String) value);
+    } else {
+      return CodedOutputStream.computeBytesSizeNoTag((ByteString) value);
+    }
+  }
+
+  protected static void writeString(
+      CodedOutputStream output, final int fieldNumber, final Object value) throws IOException {
+    if (value instanceof String) {
+      output.writeString(fieldNumber, (String) value);
+    } else {
+      output.writeBytes(fieldNumber, (ByteString) value);
+    }
+  }
+
+  protected static void writeStringNoTag(CodedOutputStream output, final Object value)
+      throws IOException {
+    if (value instanceof String) {
+      output.writeStringNoTag((String) value);
+    } else {
+      output.writeBytesNoTag((ByteString) value);
+    }
+  }
+
+  protected static <V> void serializeIntegerMapTo(
+      CodedOutputStream out,
+      MapField<Integer, V> field,
+      MapEntry<Integer, V> defaultEntry,
+      int fieldNumber)
+      throws IOException {
+    Map<Integer, V> m = field.getMap();
+    if (!out.isSerializationDeterministic()) {
+      serializeMapTo(out, m, defaultEntry, fieldNumber);
+      return;
+    }
+    // Sorting the unboxed keys and then look up the values during serialization is 2x faster
+    // than sorting map entries with a custom comparator directly.
+    int[] keys = new int[m.size()];
+    int index = 0;
+    for (int k : m.keySet()) {
+      keys[index++] = k;
+    }
+    Arrays.sort(keys);
+    for (int key : keys) {
+      out.writeMessage(
+          fieldNumber, defaultEntry.newBuilderForType().setKey(key).setValue(m.get(key)).build());
+    }
+  }
+
+  protected static <V> void serializeLongMapTo(
+      CodedOutputStream out,
+      MapField<Long, V> field,
+      MapEntry<Long, V> defaultEntry,
+      int fieldNumber)
+      throws IOException {
+    Map<Long, V> m = field.getMap();
+    if (!out.isSerializationDeterministic()) {
+      serializeMapTo(out, m, defaultEntry, fieldNumber);
+      return;
+    }
+
+    long[] keys = new long[m.size()];
+    int index = 0;
+    for (long k : m.keySet()) {
+      keys[index++] = k;
+    }
+    Arrays.sort(keys);
+    for (long key : keys) {
+      out.writeMessage(
+          fieldNumber, defaultEntry.newBuilderForType().setKey(key).setValue(m.get(key)).build());
+    }
+  }
+
+  protected static <V> void serializeStringMapTo(
+      CodedOutputStream out,
+      MapField<String, V> field,
+      MapEntry<String, V> defaultEntry,
+      int fieldNumber)
+      throws IOException {
+    Map<String, V> m = field.getMap();
+    if (!out.isSerializationDeterministic()) {
+      serializeMapTo(out, m, defaultEntry, fieldNumber);
+      return;
+    }
+
+    // Sorting the String keys and then look up the values during serialization is 25% faster than
+    // sorting map entries with a custom comparator directly.
+    String[] keys = new String[m.size()];
+    keys = m.keySet().toArray(keys);
+    Arrays.sort(keys);
+    for (String key : keys) {
+      out.writeMessage(
+          fieldNumber, defaultEntry.newBuilderForType().setKey(key).setValue(m.get(key)).build());
+    }
+  }
+
+  protected static <V> void serializeBooleanMapTo(
+      CodedOutputStream out,
+      MapField<Boolean, V> field,
+      MapEntry<Boolean, V> defaultEntry,
+      int fieldNumber)
+      throws IOException {
+    Map<Boolean, V> m = field.getMap();
+    if (!out.isSerializationDeterministic()) {
+      serializeMapTo(out, m, defaultEntry, fieldNumber);
+      return;
+    }
+    maybeSerializeBooleanEntryTo(out, m, defaultEntry, fieldNumber, false);
+    maybeSerializeBooleanEntryTo(out, m, defaultEntry, fieldNumber, true);
+  }
+
+  private static <V> void maybeSerializeBooleanEntryTo(
+      CodedOutputStream out,
+      Map<Boolean, V> m,
+      MapEntry<Boolean, V> defaultEntry,
+      int fieldNumber,
+      boolean key)
+      throws IOException {
+    if (m.containsKey(key)) {
+      out.writeMessage(
+          fieldNumber, defaultEntry.newBuilderForType().setKey(key).setValue(m.get(key)).build());
+    }
+  }
+
+  /** Serialize the map using the iteration order. */
+  private static <K, V> void serializeMapTo(
+      CodedOutputStream out, Map<K, V> m, MapEntry<K, V> defaultEntry, int fieldNumber)
+      throws IOException {
+    for (Map.Entry<K, V> entry : m.entrySet()) {
+      out.writeMessage(
+          fieldNumber,
+          defaultEntry
+              .newBuilderForType()
+              .setKey(entry.getKey())
+              .setValue(entry.getValue())
+              .build());
+    }
+  }
+}
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/Int32Value.java b/protobuf-api/src/main/java/com/google/protobuf/Int32Value.java
similarity index 94%
rename from protobuf-sdk/src/main/java/com/google/protobuf/Int32Value.java
rename to protobuf-api/src/main/java/com/google/protobuf/Int32Value.java
index e14fc28..3891573 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/Int32Value.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/Int32Value.java
@@ -14,12 +14,12 @@
  * Protobuf type {@code google.protobuf.Int32Value}
  */
 public final class Int32Value extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.Int32Value)
     Int32ValueOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use Int32Value.newBuilder() to construct.
-  private Int32Value(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private Int32Value(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private Int32Value() {
@@ -38,7 +38,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.WrappersProto.internal_static_google_protobuf_Int32Value_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -159,20 +159,20 @@ public static com.google.protobuf.Int32Value parseFrom(
   }
   public static com.google.protobuf.Int32Value parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Int32Value parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.Int32Value parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -180,20 +180,20 @@ public static com.google.protobuf.Int32Value parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.Int32Value parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Int32Value parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -213,7 +213,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -227,7 +227,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.Int32Value}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.Int32Value)
       com.google.protobuf.Int32ValueOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -236,7 +236,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.WrappersProto.internal_static_google_protobuf_Int32Value_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -249,7 +249,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/Int32ValueOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/Int32ValueOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/Int32ValueOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/Int32ValueOrBuilder.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/Int64Value.java b/protobuf-api/src/main/java/com/google/protobuf/Int64Value.java
similarity index 94%
rename from protobuf-sdk/src/main/java/com/google/protobuf/Int64Value.java
rename to protobuf-api/src/main/java/com/google/protobuf/Int64Value.java
index 0d7c811..19b499c 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/Int64Value.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/Int64Value.java
@@ -14,12 +14,12 @@
  * Protobuf type {@code google.protobuf.Int64Value}
  */
 public final class Int64Value extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.Int64Value)
     Int64ValueOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use Int64Value.newBuilder() to construct.
-  private Int64Value(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private Int64Value(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private Int64Value() {
@@ -38,7 +38,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.WrappersProto.internal_static_google_protobuf_Int64Value_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -160,20 +160,20 @@ public static com.google.protobuf.Int64Value parseFrom(
   }
   public static com.google.protobuf.Int64Value parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Int64Value parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.Int64Value parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -181,20 +181,20 @@ public static com.google.protobuf.Int64Value parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.Int64Value parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Int64Value parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -214,7 +214,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -228,7 +228,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.Int64Value}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.Int64Value)
       com.google.protobuf.Int64ValueOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -237,7 +237,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.WrappersProto.internal_static_google_protobuf_Int64Value_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -250,7 +250,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/Int64ValueOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/Int64ValueOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/Int64ValueOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/Int64ValueOrBuilder.java
diff --git a/protobuf-api/src/main/java/com/google/protobuf/Internal.java b/protobuf-api/src/main/java/com/google/protobuf/Internal.java
index 3024aa9..52da3c2 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/Internal.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/Internal.java
@@ -14,7 +14,9 @@
 import java.util.AbstractList;
 import java.util.AbstractMap;
 import java.util.AbstractSet;
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
@@ -126,6 +128,67 @@ public static ByteBuffer copyByteBuffer(ByteBuffer source) {
     return result;
   }
 
+  /**
+   * Adds the {@code values} to the {@code list}. This is a helper method used by generated code.
+   * Users should ignore it.
+   *
+   * @throws NullPointerException if {@code values} or any of the elements of {@code values} is
+   *     null.
+   */
+  public static <T> void addAll(final Iterable<T> values, final List<? super T> list) {
+    checkNotNull(values);
+    if (values instanceof LazyStringList) {
+      // For StringOrByteStringLists, check the underlying elements to avoid
+      // forcing conversions of ByteStrings to Strings.
+      // TODO: Could we just prohibit nulls in all protobuf lists and get rid of this? Is
+      // if even possible to hit this condition as all protobuf methods check for null first,
+      // right?
+      List<?> lazyValues = ((LazyStringList) values).getUnderlyingElements();
+      LazyStringList lazyList = (LazyStringList) list;
+      int begin = list.size();
+      for (Object value : lazyValues) {
+        if (value == null) {
+          // encountered a null value so we must undo our modifications prior to throwing
+          String message = "Element at index " + (lazyList.size() - begin) + " is null.";
+          for (int i = lazyList.size() - 1; i >= begin; i--) {
+            lazyList.remove(i);
+          }
+          throw new NullPointerException(message);
+        }
+        if (value instanceof ByteString) {
+          lazyList.add((ByteString) value);
+        } else {
+          lazyList.add((String) value);
+        }
+      }
+    } else {
+      if (values instanceof PrimitiveNonBoxingCollection) {
+        list.addAll((Collection<T>) values);
+      } else {
+        addAllCheckingNulls(values, list);
+      }
+    }
+  }
+
+  // We check nulls as we iterate to avoid iterating over values twice.
+  private static <T> void addAllCheckingNulls(Iterable<T> values, List<? super T> list) {
+    if (list instanceof ArrayList && values instanceof Collection) {
+      ((ArrayList<T>) list).ensureCapacity(list.size() + ((Collection<T>) values).size());
+    }
+    int begin = list.size();
+    for (T value : values) {
+      if (value == null) {
+        // encountered a null value so we must undo our modifications prior to throwing
+        String message = "Element at index " + (list.size() - begin) + " is null.";
+        for (int i = list.size() - 1; i >= begin; i--) {
+          list.remove(i);
+        }
+        throw new NullPointerException(message);
+      }
+      list.add(value);
+    }
+  }
+
   /**
    * Helper called by generated code to determine if a byte array is a valid UTF-8 encoded string
    * such that the original bytes can be converted to a String object and then back to a byte array
diff --git a/protobuf-api/src/main/java/com/google/protobuf/LazyField.java b/protobuf-api/src/main/java/com/google/protobuf/LazyField.java
index d7dddd9..1ef780c 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/LazyField.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/LazyField.java
@@ -20,7 +20,7 @@
  *
  * @author xiangl@google.com (Xiang Li)
  */
-public class LazyField extends LazyFieldLite {
+class LazyField extends LazyFieldLite {
 
   /**
    * Carry a message's default instance which is used by {@code hashCode()}, {@code equals()}, and
diff --git a/protobuf-api/src/main/java/com/google/protobuf/LimitedInputStream.java b/protobuf-api/src/main/java/com/google/protobuf/LimitedInputStream.java
new file mode 100644
index 0000000..f6eaad7
--- /dev/null
+++ b/protobuf-api/src/main/java/com/google/protobuf/LimitedInputStream.java
@@ -0,0 +1,61 @@
+package com.google.protobuf;
+
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * An InputStream implementations which reads from some other InputStream but is limited to a
+ * particular number of bytes. Used by mergeDelimitedFrom(). This is intentionally
+ * package-private so that UnknownFieldSet can share it.
+ */
+final class LimitedInputStream extends FilterInputStream {
+    private int limit;
+
+    LimitedInputStream(InputStream in, int limit) {
+        super(in);
+        this.limit = limit;
+    }
+
+    @Override
+    public int available() throws IOException {
+        return Math.min(super.available(), limit);
+    }
+
+    @Override
+    public int read() throws IOException {
+        if (limit <= 0) {
+            return -1;
+        }
+        final int result = super.read();
+        if (result >= 0) {
+            --limit;
+        }
+        return result;
+    }
+
+    @Override
+    public int read(final byte[] b, final int off, int len) throws IOException {
+        if (limit <= 0) {
+            return -1;
+        }
+        len = Math.min(len, limit);
+        final int result = super.read(b, off, len);
+        if (result >= 0) {
+            limit -= result;
+        }
+        return result;
+    }
+
+    @Override
+    public long skip(final long n) throws IOException {
+        // because we take the minimum of an int and a long, result is guaranteed to be
+        // less than or equal to Integer.MAX_INT so this cast is safe
+        int result = (int) super.skip(Math.min(n, limit));
+        if (result >= 0) {
+            // if the superclass adheres to the contract for skip, this condition is always true
+            limit -= result;
+        }
+        return result;
+    }
+}
\ No newline at end of file
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/ListValue.java b/protobuf-api/src/main/java/com/google/protobuf/ListValue.java
similarity index 94%
rename from protobuf-sdk/src/main/java/com/google/protobuf/ListValue.java
rename to protobuf-api/src/main/java/com/google/protobuf/ListValue.java
index 8a2d1d8..e4e6496 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/ListValue.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/ListValue.java
@@ -14,12 +14,12 @@
  * Protobuf type {@code google.protobuf.ListValue}
  */
 public final class ListValue extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.ListValue)
     ListValueOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use ListValue.newBuilder() to construct.
-  private ListValue(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private ListValue(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private ListValue() {
@@ -39,7 +39,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.StructProto.internal_static_google_protobuf_ListValue_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -208,20 +208,20 @@ public static com.google.protobuf.ListValue parseFrom(
   }
   public static com.google.protobuf.ListValue parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.ListValue parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.ListValue parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -229,20 +229,20 @@ public static com.google.protobuf.ListValue parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.ListValue parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.ListValue parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -262,7 +262,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -276,7 +276,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.ListValue}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.ListValue)
       com.google.protobuf.ListValueOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -285,7 +285,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.StructProto.internal_static_google_protobuf_ListValue_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -298,7 +298,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
@@ -424,7 +424,7 @@ public Builder mergeFrom(com.google.protobuf.ListValue other) {
             values_ = other.values_;
             bitField0_ = (bitField0_ & ~0x00000001);
             valuesBuilder_ = 
-              com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+              com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                  getValuesFieldBuilder() : null;
           } else {
             valuesBuilder_.addAllMessages(other.values_);
@@ -496,8 +496,8 @@ private void ensureValuesIsMutable() {
        }
     }
 
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Value, com.google.protobuf.Value.Builder, com.google.protobuf.ValueOrBuilder> valuesBuilder_;
+    private RepeatedFieldBuilderV3Internal<
+            Value, Value.Builder, ValueOrBuilder> valuesBuilder_;
 
     /**
      * <pre>
@@ -784,12 +784,12 @@ public com.google.protobuf.Value.Builder addValuesBuilder(
          getValuesBuilderList() {
       return getValuesFieldBuilder().getBuilderList();
     }
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Value, com.google.protobuf.Value.Builder, com.google.protobuf.ValueOrBuilder> 
+    private RepeatedFieldBuilderV3Internal<
+            Value, Value.Builder, ValueOrBuilder>
         getValuesFieldBuilder() {
       if (valuesBuilder_ == null) {
-        valuesBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-            com.google.protobuf.Value, com.google.protobuf.Value.Builder, com.google.protobuf.ValueOrBuilder>(
+        valuesBuilder_ = new RepeatedFieldBuilderV3Internal<
+                    Value, Value.Builder, ValueOrBuilder>(
                 values_,
                 ((bitField0_ & 0x00000001) != 0),
                 getParentForChildren(),
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/ListValueOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/ListValueOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/ListValueOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/ListValueOrBuilder.java
diff --git a/protobuf-api/src/main/java/com/google/protobuf/MapEntry.java b/protobuf-api/src/main/java/com/google/protobuf/MapEntry.java
index c065bee..a8127c9 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/MapEntry.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/MapEntry.java
@@ -10,11 +10,23 @@
 import com.google.protobuf.Descriptors.Descriptor;
 import com.google.protobuf.Descriptors.EnumValueDescriptor;
 import com.google.protobuf.Descriptors.FieldDescriptor;
+
+import java.io.FilterInputStream;
 import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
 import java.util.Map;
 import java.util.TreeMap;
 
+import static com.google.protobuf.Internal.checkNotNull;
+
 /**
  * Implements MapEntry messages.
  *
@@ -24,7 +36,7 @@
  *
  * <p>Protobuf internal. Users shouldn't use this class.
  */
-public final class MapEntry<K, V> extends AbstractMessage {
+public final class MapEntry<K, V> implements Message {
 
   private static final class Metadata<K, V> extends MapEntryLite.Metadata<K, V> {
 
@@ -216,8 +228,314 @@ public UnknownFieldSet getUnknownFields() {
     return UnknownFieldSet.getDefaultInstance();
   }
 
+  protected int memoizedHashCode = 0;
+
+  @Override
+  public ByteString toByteString() {
+    try {
+      final ByteString.CodedBuilder out = ByteString.newCodedBuilder(getSerializedSize());
+      writeTo(out.getCodedOutput());
+      return out.build();
+    } catch (IOException e) {
+      throw new RuntimeException(getSerializingExceptionMessage("ByteString"), e);
+    }
+  }
+
+  @Override
+  public byte[] toByteArray() {
+    try {
+      final byte[] result = new byte[getSerializedSize()];
+      final CodedOutputStream output = CodedOutputStream.newInstance(result);
+      writeTo(output);
+      output.checkNoSpaceLeft();
+      return result;
+    } catch (IOException e) {
+      throw new RuntimeException(getSerializingExceptionMessage("byte array"), e);
+    }
+  }
+
+  @Override
+  public void writeTo(final OutputStream output) throws IOException {
+    final int bufferSize = CodedOutputStream.computePreferredBufferSize(getSerializedSize());
+    final CodedOutputStream codedOutput = CodedOutputStream.newInstance(output, bufferSize);
+    writeTo(codedOutput);
+    codedOutput.flush();
+  }
+
+  @Override
+  public void writeDelimitedTo(final OutputStream output) throws IOException {
+    final int serialized = getSerializedSize();
+    final int bufferSize =
+            CodedOutputStream.computePreferredBufferSize(
+                    CodedOutputStream.computeUInt32SizeNoTag(serialized) + serialized);
+    final CodedOutputStream codedOutput = CodedOutputStream.newInstance(output, bufferSize);
+    codedOutput.writeUInt32NoTag(serialized);
+    writeTo(codedOutput);
+    codedOutput.flush();
+  }
+
+  int getSerializedSize(
+          Schema schema) {
+    int memoizedSerializedSize = getMemoizedSerializedSize();
+    if (memoizedSerializedSize == -1) {
+      memoizedSerializedSize = schema.getSerializedSize(this);
+      setMemoizedSerializedSize(memoizedSerializedSize);
+    }
+    return memoizedSerializedSize;
+  }
+
+  private String getSerializingExceptionMessage(String target) {
+    return "Serializing "
+            + getClass().getName()
+            + " to a "
+            + target
+            + " threw an IOException (should never happen).";
+  }
+
+  protected static void checkByteStringIsUtf8(ByteString byteString)
+          throws IllegalArgumentException {
+    if (!byteString.isValidUtf8()) {
+      throw new IllegalArgumentException("Byte string is not UTF-8.");
+    }
+  }
+
+  /** Interface for an enum which signifies which field in a {@code oneof} was specified. */
+  protected interface InternalOneOfEnum {
+    /**
+     * Retrieves the field number of the field which was set in this {@code oneof}, or {@code 0} if
+     * none were.
+     */
+    int getNumber();
+  }
+
+  /**
+   * Interface for the parent of a Builder that allows the builder to communicate invalidations back
+   * to the parent for use when using nested builders.
+   */
+  protected interface BuilderParent {
+
+    /**
+     * A builder becomes dirty whenever a field is modified -- including fields in nested builders
+     * -- and becomes clean when build() is called. Thus, when a builder becomes dirty, all its
+     * parents become dirty as well, and when it becomes clean, all its children become clean. The
+     * dirtiness state is used to invalidate certain cached values.
+     *
+     * <p>To this end, a builder calls markDirty() on its parent whenever it transitions from clean
+     * to dirty. The parent must propagate this call to its own parent, unless it was already dirty,
+     * in which case the grandparent must necessarily already be dirty as well. The parent can only
+     * transition back to "clean" after calling build() on all children.
+     */
+    void markDirty();
+  }
+
+  @Override
+  public List<String> findInitializationErrors() {
+    return MessageReflection.findMissingFields(this);
+  }
+
+  @Override
+  public String getInitializationErrorString() {
+    return MessageReflection.delimitWithCommas(findInitializationErrors());
+  }
+
+  // TODO: Clear it when all subclasses have implemented this method.
+  @Override
+  public boolean hasOneof(Descriptors.OneofDescriptor oneof) {
+    throw new UnsupportedOperationException("hasOneof() is not implemented.");
+  }
+
+  // TODO: Clear it when all subclasses have implemented this method.
+  @Override
+  public FieldDescriptor getOneofFieldDescriptor(Descriptors.OneofDescriptor oneof) {
+    throw new UnsupportedOperationException("getOneofFieldDescriptor() is not implemented.");
+  }
+
+  @Override
+  public final String toString() {
+    return TextFormatInternal.printer().printToString(this);
+  }
+
+  protected int memoizedSize = -1;
+
+  int getMemoizedSerializedSize() {
+    return memoizedSize;
+  }
+
+  void setMemoizedSerializedSize(int size) {
+    memoizedSize = size;
+  }
+
+  @Override
+  public boolean equals(final Object other) {
+    if (other == this) {
+      return true;
+    }
+    if (!(other instanceof Message)) {
+      return false;
+    }
+    final Message otherMessage = (Message) other;
+    if (getDescriptorForType() != otherMessage.getDescriptorForType()) {
+      return false;
+    }
+    return compareFields(getAllFields(), otherMessage.getAllFields())
+            && getUnknownFields().equals(otherMessage.getUnknownFields());
+  }
+
+  @Override
+  public int hashCode() {
+    int hash = memoizedHashCode;
+    if (hash == 0) {
+      hash = 41;
+      hash = (19 * hash) + getDescriptorForType().hashCode();
+      hash = hashFields(hash, getAllFields());
+      hash = (29 * hash) + getUnknownFields().hashCode();
+      memoizedHashCode = hash;
+    }
+    return hash;
+  }
+
+  private static ByteString toByteString(Object value) {
+    if (value instanceof byte[]) {
+      return ByteString.copyFrom((byte[]) value);
+    } else {
+      return (ByteString) value;
+    }
+  }
+
+  /**
+   * Compares two bytes fields. The parameters must be either a byte array or a ByteString object.
+   * They can be of different type though.
+   */
+  private static boolean compareBytes(Object a, Object b) {
+    if (a instanceof byte[] && b instanceof byte[]) {
+      return Arrays.equals((byte[]) a, (byte[]) b);
+    }
+    return toByteString(a).equals(toByteString(b));
+  }
+
+  /** Converts a list of MapEntry messages into a Map used for equals() and hashCode(). */
+  @SuppressWarnings({"rawtypes", "unchecked"})
+  private static Map convertMapEntryListToMap(List list) {
+    if (list.isEmpty()) {
+      return Collections.emptyMap();
+    }
+    Map result = new HashMap<>();
+    Iterator iterator = list.iterator();
+    Message entry = (Message) iterator.next();
+    Descriptors.Descriptor descriptor = entry.getDescriptorForType();
+    FieldDescriptor key = descriptor.findFieldByName("key");
+    FieldDescriptor value = descriptor.findFieldByName("value");
+    Object fieldValue = entry.getField(value);
+    if (fieldValue instanceof EnumValueDescriptor) {
+      fieldValue = ((EnumValueDescriptor) fieldValue).getNumber();
+    }
+    result.put(entry.getField(key), fieldValue);
+    while (iterator.hasNext()) {
+      entry = (Message) iterator.next();
+      fieldValue = entry.getField(value);
+      if (fieldValue instanceof EnumValueDescriptor) {
+        fieldValue = ((EnumValueDescriptor) fieldValue).getNumber();
+      }
+      result.put(entry.getField(key), fieldValue);
+    }
+    return result;
+  }
+
+  /** Compares two map fields. The parameters must be a list of MapEntry messages. */
+  @SuppressWarnings({"rawtypes", "unchecked"})
+  private static boolean compareMapField(Object a, Object b) {
+    Map ma = convertMapEntryListToMap((List) a);
+    Map mb = convertMapEntryListToMap((List) b);
+    return MapFieldLite.equals(ma, mb);
+  }
+
+  /**
+   * Compares two sets of fields. This method is used to implement {@link
+   * Message#equals(Object)} and {@link AbstractMutableMessage#equals(Object)}. It takes
+   * special care of bytes fields because immutable messages and mutable messages use different Java
+   * type to represent a bytes field and this method should be able to compare immutable messages,
+   * mutable messages and also an immutable message to a mutable message.
+   */
+  static boolean compareFields(Map<FieldDescriptor, Object> a, Map<FieldDescriptor, Object> b) {
+    if (a.size() != b.size()) {
+      return false;
+    }
+    for (FieldDescriptor descriptor : a.keySet()) {
+      if (!b.containsKey(descriptor)) {
+        return false;
+      }
+      Object value1 = a.get(descriptor);
+      Object value2 = b.get(descriptor);
+      if (descriptor.getType() == FieldDescriptor.Type.BYTES) {
+        if (descriptor.isRepeated()) {
+          List<?> list1 = (List) value1;
+          List<?> list2 = (List) value2;
+          if (list1.size() != list2.size()) {
+            return false;
+          }
+          for (int i = 0; i < list1.size(); i++) {
+            if (!compareBytes(list1.get(i), list2.get(i))) {
+              return false;
+            }
+          }
+        } else {
+          // Compares a singular bytes field.
+          if (!compareBytes(value1, value2)) {
+            return false;
+          }
+        }
+      } else if (descriptor.isMapField()) {
+        if (!compareMapField(value1, value2)) {
+          return false;
+        }
+      } else {
+        // Compare non-bytes fields.
+        if (!value1.equals(value2)) {
+          return false;
+        }
+      }
+    }
+    return true;
+  }
+
+  /** Calculates the hash code of a map field. {@code value} must be a list of MapEntry messages. */
+  @SuppressWarnings("unchecked")
+  private static int hashMapField(Object value) {
+    return MapFieldLite.calculateHashCodeForMap(convertMapEntryListToMap((List) value));
+  }
+
+  /** Get a hash code for given fields and values, using the given seed. */
+  @SuppressWarnings("unchecked")
+  protected static int hashFields(int hash, Map<FieldDescriptor, Object> map) {
+    for (Map.Entry<FieldDescriptor, Object> entry : map.entrySet()) {
+      FieldDescriptor field = entry.getKey();
+      Object value = entry.getValue();
+      hash = (37 * hash) + field.getNumber();
+      if (field.isMapField()) {
+        hash = (53 * hash) + hashMapField(value);
+      } else if (field.getType() != FieldDescriptor.Type.ENUM) {
+        hash = (53 * hash) + value.hashCode();
+      } else if (field.isRepeated()) {
+        List<? extends Internal.EnumLite> list = (List<? extends Internal.EnumLite>) value;
+        hash = (53 * hash) + Internal.hashEnumList(list);
+      } else {
+        hash = (53 * hash) + Internal.hashEnum((Internal.EnumLite) value);
+      }
+    }
+    return hash;
+  }
+
+  /**
+   * Package private helper method for AbstractParser to create UninitializedMessageException with
+   * missing field information.
+   */
+  UninitializedMessageException newUninitializedMessageException() {
+    return Builder.newUninitializedMessageException(this);
+  }
+
+
   /** Builder to create {@link MapEntry} messages. */
-  public static class Builder<K, V> extends AbstractMessage.Builder<Builder<K, V>> {
+  public static class Builder<K, V> implements Message.Builder {
     private final Metadata<K, V> metadata;
     private K key;
     private V value;
@@ -417,10 +735,387 @@ public UnknownFieldSet getUnknownFields() {
       return UnknownFieldSet.getDefaultInstance();
     }
 
-    @Override
     public Builder<K, V> clone() {
       return new Builder<>(metadata, key, value, hasKey, hasValue);
     }
+
+    @Override
+    public boolean mergeDelimitedFrom(
+            final InputStream input, final ExtensionRegistryLite extensionRegistry) throws IOException {
+      final int firstByte = input.read();
+      if (firstByte == -1) {
+        return false;
+      }
+      final int size = CodedInputStream.readRawVarint32(firstByte, input);
+      final InputStream limitedInput = new LimitedInputStream(input, size);
+      mergeFrom(limitedInput, extensionRegistry);
+      return true;
+    }
+
+    @Override
+    public boolean mergeDelimitedFrom(final InputStream input) throws IOException {
+      return mergeDelimitedFrom(input, ExtensionRegistryLite.getEmptyRegistry());
+    }
+
+    @Override
+    @SuppressWarnings("unchecked") // isInstance takes care of this
+    public MapEntry.Builder<K,V> mergeFrom(final MessageLite other) {
+      if (!getDefaultInstanceForType().getClass().isInstance(other)) {
+        throw new IllegalArgumentException(
+                "mergeFrom(MessageLite) can only merge messages of the same type.");
+      }
+
+      return internalMergeFrom(other);
+    }
+
+    private String getReadingExceptionMessage(String target) {
+      return "Reading "
+              + getClass().getName()
+              + " from a "
+              + target
+              + " threw an IOException (should never happen).";
+    }
+
+    // We check nulls as we iterate to avoid iterating over values twice.
+    private static <T> void addAllCheckingNulls(Iterable<T> values, List<? super T> list) {
+      if (list instanceof ArrayList && values instanceof Collection) {
+        ((ArrayList<T>) list).ensureCapacity(list.size() + ((Collection<T>) values).size());
+      }
+      int begin = list.size();
+      for (T value : values) {
+        if (value == null) {
+          // encountered a null value so we must undo our modifications prior to throwing
+          String message = "Element at index " + (list.size() - begin) + " is null.";
+          for (int i = list.size() - 1; i >= begin; i--) {
+            list.remove(i);
+          }
+          throw new NullPointerException(message);
+        }
+        list.add(value);
+      }
+    }
+
+    /** Construct an UninitializedMessageException reporting missing fields in the given message. */
+    protected static UninitializedMessageException newUninitializedMessageException(
+            MessageLite message) {
+      return new UninitializedMessageException(message);
+    }
+
+    // For binary compatibility.
+    @Deprecated
+    protected static <T> void addAll(final Iterable<T> values, final Collection<? super T> list) {
+      addAll(values, (List<T>) list);
+    }
+
+    /**
+     * Adds the {@code values} to the {@code list}. This is a helper method used by generated code.
+     * Users should ignore it.
+     *
+     * @throws NullPointerException if {@code values} or any of the elements of {@code values} is
+     *     null.
+     */
+    protected static <T> void addAll(final Iterable<T> values, final List<? super T> list) {
+      checkNotNull(values);
+      if (values instanceof LazyStringList) {
+        // For StringOrByteStringLists, check the underlying elements to avoid
+        // forcing conversions of ByteStrings to Strings.
+        // TODO: Could we just prohibit nulls in all protobuf lists and get rid of this? Is
+        // if even possible to hit this condition as all protobuf methods check for null first,
+        // right?
+        List<?> lazyValues = ((LazyStringList) values).getUnderlyingElements();
+        LazyStringList lazyList = (LazyStringList) list;
+        int begin = list.size();
+        for (Object value : lazyValues) {
+          if (value == null) {
+            // encountered a null value so we must undo our modifications prior to throwing
+            String message = "Element at index " + (lazyList.size() - begin) + " is null.";
+            for (int i = lazyList.size() - 1; i >= begin; i--) {
+              lazyList.remove(i);
+            }
+            throw new NullPointerException(message);
+          }
+          if (value instanceof ByteString) {
+            lazyList.add((ByteString) value);
+          } else {
+            lazyList.add((String) value);
+          }
+        }
+      } else {
+        if (values instanceof PrimitiveNonBoxingCollection) {
+          list.addAll((Collection<T>) values);
+        } else {
+          addAllCheckingNulls(values, list);
+        }
+      }
+    }
+
+    /** TODO: Clear it when all subclasses have implemented this method. */
+    @Override
+    public boolean hasOneof(Descriptors.OneofDescriptor oneof) {
+      throw new UnsupportedOperationException("hasOneof() is not implemented.");
+    }
+
+    /** TODO: Clear it when all subclasses have implemented this method. */
+    @Override
+    public FieldDescriptor getOneofFieldDescriptor(Descriptors.OneofDescriptor oneof) {
+      throw new UnsupportedOperationException("getOneofFieldDescriptor() is not implemented.");
+    }
+
+    /** TODO: Clear it when all subclasses have implemented this method. */
+    @Override
+    public MapEntry.Builder<K,V> clearOneof(Descriptors.OneofDescriptor oneof) {
+      throw new UnsupportedOperationException("clearOneof() is not implemented.");
+    }
+
+    @Override
+    public MapEntry.Builder<K,V> clear() {
+      for (final Map.Entry<FieldDescriptor, Object> entry : getAllFields().entrySet()) {
+        clearField(entry.getKey());
+      }
+      return (MapEntry.Builder<K,V>) this;
+    }
+
+    @Override
+    public List<String> findInitializationErrors() {
+      return MessageReflection.findMissingFields(this);
+    }
+
+    @Override
+    public String getInitializationErrorString() {
+      return MessageReflection.delimitWithCommas(findInitializationErrors());
+    }
+
+    protected MapEntry.Builder<K,V> internalMergeFrom(MessageLite other) {
+      return mergeFrom((Message) other);
+    }
+
+    @Override
+    public MapEntry.Builder<K,V> mergeFrom(final Message other) {
+      return mergeFrom(other, other.getAllFields());
+    }
+
+    MapEntry.Builder<K,V> mergeFrom(final Message other, Map<FieldDescriptor, Object> allFields) {
+      if (other.getDescriptorForType() != getDescriptorForType()) {
+        throw new IllegalArgumentException(
+                "mergeFrom(Message) can only merge messages of the same type.");
+      }
+
+      // Note:  We don't attempt to verify that other's fields have valid
+      //   types.  Doing so would be a losing battle.  We'd have to verify
+      //   all sub-messages as well, and we'd have to make copies of all of
+      //   them to insure that they don't change after verification (since
+      //   the Message interface itself cannot enforce immutability of
+      //   implementations).
+
+      for (final Map.Entry<FieldDescriptor, Object> entry : allFields.entrySet()) {
+        final FieldDescriptor field = entry.getKey();
+        if (field.isRepeated()) {
+          for (final Object element : (List) entry.getValue()) {
+            addRepeatedField(field, element);
+          }
+        } else if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+          final Message existingValue = (Message) getField(field);
+          if (existingValue == existingValue.getDefaultInstanceForType()) {
+            setField(field, entry.getValue());
+          } else {
+            setField(
+                    field,
+                    existingValue
+                            .newBuilderForType()
+                            .mergeFrom(existingValue)
+                            .mergeFrom((Message) entry.getValue())
+                            .build());
+          }
+        } else {
+          setField(field, entry.getValue());
+        }
+      }
+
+      mergeUnknownFields(other.getUnknownFields());
+
+      return (MapEntry.Builder<K,V>) this;
+    }
+
+    @Override
+    public MapEntry.Builder<K,V> mergeFrom(final CodedInputStream input) throws IOException {
+      return mergeFrom(input, ExtensionRegistry.getEmptyRegistry());
+    }
+
+    @Override
+    public MapEntry.Builder<K,V> mergeFrom(
+            final CodedInputStream input, final ExtensionRegistryLite extensionRegistry)
+            throws IOException {
+      boolean discardUnknown = input.shouldDiscardUnknownFields();
+      final UnknownFieldSet.Builder unknownFields =
+              discardUnknown ? null : getUnknownFieldSetBuilder();
+      MessageReflection.mergeMessageFrom(this, unknownFields, input, extensionRegistry);
+      if (unknownFields != null) {
+        setUnknownFieldSetBuilder(unknownFields);
+      }
+      return (MapEntry.Builder<K,V>) this;
+    }
+
+    protected UnknownFieldSet.Builder getUnknownFieldSetBuilder() {
+      return UnknownFieldSet.newBuilder(getUnknownFields());
+    }
+
+    protected void setUnknownFieldSetBuilder(final UnknownFieldSet.Builder builder) {
+      setUnknownFields(builder.build());
+    }
+
+    @Override
+    public MapEntry.Builder<K,V> mergeUnknownFields(final UnknownFieldSet unknownFields) {
+      setUnknownFields(
+              UnknownFieldSet.newBuilder(getUnknownFields()).mergeFrom(unknownFields).build());
+      return (MapEntry.Builder<K,V>) this;
+    }
+
+    @Override
+    public MapEntry.Builder<K,V> getFieldBuilder(final FieldDescriptor field) {
+      throw new UnsupportedOperationException(
+              "getFieldBuilder() called on an unsupported message type.");
+    }
+
+    @Override
+    public MapEntry.Builder<K,V> getRepeatedFieldBuilder(final FieldDescriptor field, int index) {
+      throw new UnsupportedOperationException(
+              "getRepeatedFieldBuilder() called on an unsupported message type.");
+    }
+
+    @Override
+    public String toString() {
+      return TextFormatInternal.printer().printToString(this);
+    }
+
+    /** Construct an UninitializedMessageException reporting missing fields in the given message. */
+    protected static UninitializedMessageException newUninitializedMessageException(
+            Message message) {
+      return new UninitializedMessageException(MessageReflection.findMissingFields(message));
+    }
+
+    public MapEntry.Builder<K,V> mergeFrom(final ByteString data) throws InvalidProtocolBufferException {
+      try {
+        final CodedInputStream input = data.newCodedInput();
+        mergeFrom(input);
+        input.checkLastTagWas(0);
+        return (MapEntry.Builder<K,V>) this;
+      } catch (InvalidProtocolBufferException e) {
+        throw e;
+      } catch (IOException e) {
+        throw new RuntimeException(getReadingExceptionMessage("ByteString"), e);
+      }
+    }
+
+    public MapEntry.Builder<K,V> mergeFrom(
+            final ByteString data, final ExtensionRegistryLite extensionRegistry)
+            throws InvalidProtocolBufferException {
+      try {
+        final CodedInputStream input = data.newCodedInput();
+        mergeFrom(input, extensionRegistry);
+        input.checkLastTagWas(0);
+        return (MapEntry.Builder<K,V>) this;
+      } catch (InvalidProtocolBufferException e) {
+        throw e;
+      } catch (IOException e) {
+        throw new RuntimeException(getReadingExceptionMessage("ByteString"), e);
+      }
+    }
+
+    public MapEntry.Builder<K,V> mergeFrom(final byte[] data) throws InvalidProtocolBufferException {
+      return mergeFrom(data, 0, data.length);
+    }
+
+    public MapEntry.Builder<K,V> mergeFrom(final byte[] data, final int off, final int len)
+            throws InvalidProtocolBufferException {
+      try {
+        final CodedInputStream input = CodedInputStream.newInstance(data, off, len);
+        mergeFrom(input);
+        input.checkLastTagWas(0);
+        return (MapEntry.Builder<K,V>) this;
+      } catch (InvalidProtocolBufferException e) {
+        throw e;
+      } catch (IOException e) {
+        throw new RuntimeException(getReadingExceptionMessage("byte array"), e);
+      }
+    }
+
+    public MapEntry.Builder<K,V> mergeFrom(final byte[] data, final ExtensionRegistryLite extensionRegistry)
+            throws InvalidProtocolBufferException {
+      return mergeFrom(data, 0, data.length, extensionRegistry);
+    }
+
+    public MapEntry.Builder<K,V> mergeFrom(
+            final byte[] data,
+            final int off,
+            final int len,
+            final ExtensionRegistryLite extensionRegistry)
+            throws InvalidProtocolBufferException {
+      try {
+        final CodedInputStream input = CodedInputStream.newInstance(data, off, len);
+        mergeFrom(input, extensionRegistry);
+        input.checkLastTagWas(0);
+        return (MapEntry.Builder<K,V>) this;
+      } catch (InvalidProtocolBufferException e) {
+        throw e;
+      } catch (IOException e) {
+        throw new RuntimeException(getReadingExceptionMessage("byte array"), e);
+      }
+    }
+
+    public MapEntry.Builder<K,V> mergeFrom(final InputStream input) throws IOException {
+      final CodedInputStream codedInput = CodedInputStream.newInstance(input);
+      mergeFrom(codedInput);
+      codedInput.checkLastTagWas(0);
+      return (MapEntry.Builder<K,V>) this;
+    }
+
+    public MapEntry.Builder<K,V> mergeFrom(
+            final InputStream input, final ExtensionRegistryLite extensionRegistry) throws IOException {
+      final CodedInputStream codedInput = CodedInputStream.newInstance(input);
+      mergeFrom(codedInput, extensionRegistry);
+      codedInput.checkLastTagWas(0);
+      return (MapEntry.Builder<K,V>) this;
+    }
+
+    /**
+     * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
+     * generated code.
+     */
+    @Deprecated
+    protected static int hashLong(long n) {
+      return (int) (n ^ (n >>> 32));
+    }
+
+    /**
+     * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
+     * generated code.
+     */
+    @Deprecated
+    protected static int hashBoolean(boolean b) {
+      return b ? 1231 : 1237;
+    }
+
+    /**
+     * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
+     * generated code.
+     */
+    @Deprecated
+    protected static int hashEnum(Internal.EnumLite e) {
+      return e.getNumber();
+    }
+
+    /**
+     * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
+     * generated code.
+     */
+    @Deprecated
+    protected static int hashEnumList(List<? extends Internal.EnumLite> list) {
+      int hash = 1;
+      for (Internal.EnumLite e : list) {
+        hash = 31 * hash + hashEnum(e);
+      }
+      return hash;
+    }
   }
 
   private static <V> boolean isInitialized(Metadata metadata, V value) {
diff --git a/protobuf-api/src/main/java/com/google/protobuf/MapEntryLite.java b/protobuf-api/src/main/java/com/google/protobuf/MapEntryLite.java
index 99f3460..61b1f65 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/MapEntryLite.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/MapEntryLite.java
@@ -19,7 +19,7 @@
  *
  * <p>Protobuf internal. Users shouldn't use.
  */
-public class MapEntryLite<K, V> {
+class MapEntryLite<K, V> {
 
   static class Metadata<K, V> {
     public final WireFormat.FieldType keyType;
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/MapFieldBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/MapFieldBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/MapFieldBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/MapFieldBuilder.java
diff --git a/protobuf-api/src/main/java/com/google/protobuf/MapFieldLite.java b/protobuf-api/src/main/java/com/google/protobuf/MapFieldLite.java
index bc5704b..a94825c 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/MapFieldLite.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/MapFieldLite.java
@@ -21,7 +21,7 @@
  *
  * <p>This class is a protobuf implementation detail. Users shouldn't use this class directly.
  */
-public final class MapFieldLite<K, V> extends LinkedHashMap<K, V> {
+final class MapFieldLite<K, V> extends LinkedHashMap<K, V> {
 
   private boolean isMutable;
 
diff --git a/protobuf-api/src/main/java/com/google/protobuf/Message.java b/protobuf-api/src/main/java/com/google/protobuf/Message.java
index 5b02c46..830587e 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/Message.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/Message.java
@@ -24,6 +24,26 @@
 @CheckReturnValue
 public interface Message extends MessageLite, MessageOrBuilder {
 
+  /**
+   * Interface for the parent of a Builder that allows the builder to communicate invalidations back
+   * to the parent for use when using nested builders.
+   */
+   interface BuilderParent {
+
+    /**
+     * A builder becomes dirty whenever a field is modified -- including fields in nested builders
+     * -- and becomes clean when build() is called. Thus, when a builder becomes dirty, all its
+     * parents become dirty as well, and when it becomes clean, all its children become clean. The
+     * dirtiness state is used to invalidate certain cached values.
+     *
+     * <p>To this end, a builder calls markDirty() on its parent whenever it transitions from clean
+     * to dirty. The parent must propagate this call to its own parent, unless it was already dirty,
+     * in which case the grandparent must necessarily already be dirty as well. The parent can only
+     * transition back to "clean" after calling build() on all children.
+     */
+    void markDirty();
+  }
+
   // (From MessageLite, re-declared here only for return type covariance.)
   @Override
   Parser<? extends Message> getParserForType();
@@ -64,6 +84,10 @@ public interface Message extends MessageLite, MessageOrBuilder {
   @Override
   String toString();
 
+  default boolean isGenerated() {
+    return false;
+  }
+
   // =================================================================
   // Builders
 
@@ -71,11 +95,39 @@ public interface Message extends MessageLite, MessageOrBuilder {
   @Override
   Builder newBuilderForType();
 
+  default Message.Builder newBuilderForType(BuilderParent parent) {
+    throw new UnsupportedOperationException("Nested builder is not supported for this type.");
+  }
+
   @Override
   Builder toBuilder();
 
   /** Abstract interface implemented by Protocol Message builders. */
   interface Builder extends MessageLite.Builder, MessageOrBuilder {
+
+    /**
+     * Used to support nested builders and called to mark this builder as clean. Clean builders will
+     * propagate the {@link BuilderParent#markDirty()} event to their parent builders, while dirty
+     * builders will not, as their parents should be dirty already.
+     *
+     * <p>NOTE: Implementations that don't support nested builders don't need to override this
+     * method.
+     */
+    default void markClean() {
+      throw new IllegalStateException("Should be overridden by subclasses.");
+    }
+
+    /**
+     * Used to support nested builders and called when this nested builder is no longer used by its
+     * parent builder and should release the reference to its parent builder.
+     *
+     * <p>NOTE: Implementations that don't support nested builders don't need to override this
+     * method.
+     */
+    default void dispose() {
+      throw new IllegalStateException("Should be overridden by subclasses.");
+    }
+
     // (From MessageLite.Builder, re-declared here only for return type
     // covariance.)
     @Override
@@ -263,5 +315,9 @@ Builder mergeFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
     @Override
     boolean mergeDelimitedFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
         throws IOException;
+
+    default boolean isGenerated() {
+      return false;
+    }
   }
 }
diff --git a/protobuf-api/src/main/java/com/google/protobuf/MessageReflection.java b/protobuf-api/src/main/java/com/google/protobuf/MessageReflection.java
index e33cc45..7dad81d 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/MessageReflection.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/MessageReflection.java
@@ -638,7 +638,7 @@ public WireFormat.Utf8Validation getUtf8Validation(Descriptors.FieldDescriptor d
         return WireFormat.Utf8Validation.STRICT;
       }
       // TODO: support lazy strings for repeated fields.
-      if (!descriptor.isRepeated() && builder instanceof GeneratedMessage.Builder) {
+      if (!descriptor.isRepeated() && builder.isGenerated()) {
         return WireFormat.Utf8Validation.LAZY;
       }
       return WireFormat.Utf8Validation.LOOSE;
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/Method.java b/protobuf-api/src/main/java/com/google/protobuf/Method.java
similarity index 95%
rename from protobuf-sdk/src/main/java/com/google/protobuf/Method.java
rename to protobuf-api/src/main/java/com/google/protobuf/Method.java
index 541f0f1..f38d63b 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/Method.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/Method.java
@@ -12,12 +12,12 @@
  * Protobuf type {@code google.protobuf.Method}
  */
 public final class Method extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.Method)
     MethodOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use Method.newBuilder() to construct.
-  private Method(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private Method(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private Method() {
@@ -41,7 +41,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.ApiProto.internal_static_google_protobuf_Method_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -320,17 +320,17 @@ public final boolean isInitialized() {
   @java.lang.Override
   public void writeTo(com.google.protobuf.CodedOutputStream output)
                       throws java.io.IOException {
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 1, name_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(name_)) {
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, name_);
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(requestTypeUrl_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 2, requestTypeUrl_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(requestTypeUrl_)) {
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 2, requestTypeUrl_);
     }
     if (requestStreaming_ != false) {
       output.writeBool(3, requestStreaming_);
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(responseTypeUrl_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 4, responseTypeUrl_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(responseTypeUrl_)) {
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 4, responseTypeUrl_);
     }
     if (responseStreaming_ != false) {
       output.writeBool(5, responseStreaming_);
@@ -350,18 +350,18 @@ public int getSerializedSize() {
     if (size != -1) return size;
 
     size = 0;
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, name_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(name_)) {
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(1, name_);
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(requestTypeUrl_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(2, requestTypeUrl_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(requestTypeUrl_)) {
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(2, requestTypeUrl_);
     }
     if (requestStreaming_ != false) {
       size += com.google.protobuf.CodedOutputStream
         .computeBoolSize(3, requestStreaming_);
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(responseTypeUrl_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(4, responseTypeUrl_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(responseTypeUrl_)) {
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(4, responseTypeUrl_);
     }
     if (responseStreaming_ != false) {
       size += com.google.protobuf.CodedOutputStream
@@ -471,20 +471,20 @@ public static com.google.protobuf.Method parseFrom(
   }
   public static com.google.protobuf.Method parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Method parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.Method parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -492,20 +492,20 @@ public static com.google.protobuf.Method parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.Method parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Method parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -525,7 +525,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -537,7 +537,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.Method}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.Method)
       com.google.protobuf.MethodOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -546,7 +546,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.ApiProto.internal_static_google_protobuf_Method_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -559,7 +559,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
@@ -730,7 +730,7 @@ public Builder mergeFrom(com.google.protobuf.Method other) {
             options_ = other.options_;
             bitField0_ = (bitField0_ & ~0x00000020);
             optionsBuilder_ = 
-              com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+              com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                  getOptionsFieldBuilder() : null;
           } else {
             optionsBuilder_.addAllMessages(other.options_);
@@ -1199,8 +1199,8 @@ private void ensureOptionsIsMutable() {
        }
     }
 
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Option, com.google.protobuf.Option.Builder, com.google.protobuf.OptionOrBuilder> optionsBuilder_;
+    private RepeatedFieldBuilderV3Internal<
+            Option, Option.Builder, OptionOrBuilder> optionsBuilder_;
 
     /**
      * <pre>
@@ -1487,12 +1487,12 @@ public com.google.protobuf.Option.Builder addOptionsBuilder(
          getOptionsBuilderList() {
       return getOptionsFieldBuilder().getBuilderList();
     }
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Option, com.google.protobuf.Option.Builder, com.google.protobuf.OptionOrBuilder> 
+    private RepeatedFieldBuilderV3Internal<
+            Option, Option.Builder, OptionOrBuilder>
         getOptionsFieldBuilder() {
       if (optionsBuilder_ == null) {
-        optionsBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-            com.google.protobuf.Option, com.google.protobuf.Option.Builder, com.google.protobuf.OptionOrBuilder>(
+        optionsBuilder_ = new RepeatedFieldBuilderV3Internal<
+                    Option, Option.Builder, OptionOrBuilder>(
                 options_,
                 ((bitField0_ & 0x00000020) != 0),
                 getParentForChildren(),
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/MethodOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/MethodOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/MethodOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/MethodOrBuilder.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/Mixin.java b/protobuf-api/src/main/java/com/google/protobuf/Mixin.java
similarity index 94%
rename from protobuf-sdk/src/main/java/com/google/protobuf/Mixin.java
rename to protobuf-api/src/main/java/com/google/protobuf/Mixin.java
index 56f92d0..b73f95d 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/Mixin.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/Mixin.java
@@ -89,12 +89,12 @@
  * Protobuf type {@code google.protobuf.Mixin}
  */
 public final class Mixin extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.Mixin)
     MixinOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use Mixin.newBuilder() to construct.
-  private Mixin(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private Mixin(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private Mixin() {
@@ -115,7 +115,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.ApiProto.internal_static_google_protobuf_Mixin_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -232,11 +232,11 @@ public final boolean isInitialized() {
   @java.lang.Override
   public void writeTo(com.google.protobuf.CodedOutputStream output)
                       throws java.io.IOException {
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 1, name_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(name_)) {
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, name_);
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(root_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 2, root_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(root_)) {
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 2, root_);
     }
     getUnknownFields().writeTo(output);
   }
@@ -247,11 +247,11 @@ public int getSerializedSize() {
     if (size != -1) return size;
 
     size = 0;
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, name_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(name_)) {
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(1, name_);
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(root_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(2, root_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(root_)) {
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(2, root_);
     }
     size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
@@ -326,20 +326,20 @@ public static com.google.protobuf.Mixin parseFrom(
   }
   public static com.google.protobuf.Mixin parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Mixin parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.Mixin parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -347,20 +347,20 @@ public static com.google.protobuf.Mixin parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.Mixin parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Mixin parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -380,7 +380,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -469,7 +469,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.Mixin}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.Mixin)
       com.google.protobuf.MixinOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -478,7 +478,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.ApiProto.internal_static_google_protobuf_Mixin_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -491,7 +491,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/MixinOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/MixinOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/MixinOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/MixinOrBuilder.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/NullValue.java b/protobuf-api/src/main/java/com/google/protobuf/NullValue.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/NullValue.java
rename to protobuf-api/src/main/java/com/google/protobuf/NullValue.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/Option.java b/protobuf-api/src/main/java/com/google/protobuf/Option.java
similarity index 94%
rename from protobuf-sdk/src/main/java/com/google/protobuf/Option.java
rename to protobuf-api/src/main/java/com/google/protobuf/Option.java
index 119fbaf..331d8aa 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/Option.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/Option.java
@@ -13,12 +13,12 @@
  * Protobuf type {@code google.protobuf.Option}
  */
 public final class Option extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.Option)
     OptionOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use Option.newBuilder() to construct.
-  private Option(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private Option(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private Option() {
@@ -38,7 +38,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.TypeProto.internal_static_google_protobuf_Option_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -160,8 +160,8 @@ public final boolean isInitialized() {
   @java.lang.Override
   public void writeTo(com.google.protobuf.CodedOutputStream output)
                       throws java.io.IOException {
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 1, name_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(name_)) {
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, name_);
     }
     if (((bitField0_ & 0x00000001) != 0)) {
       output.writeMessage(2, getValue());
@@ -175,8 +175,8 @@ public int getSerializedSize() {
     if (size != -1) return size;
 
     size = 0;
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, name_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(name_)) {
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(1, name_);
     }
     if (((bitField0_ & 0x00000001) != 0)) {
       size += com.google.protobuf.CodedOutputStream
@@ -260,20 +260,20 @@ public static com.google.protobuf.Option parseFrom(
   }
   public static com.google.protobuf.Option parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Option parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.Option parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -281,20 +281,20 @@ public static com.google.protobuf.Option parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.Option parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Option parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -314,7 +314,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -327,7 +327,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.Option}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.Option)
       com.google.protobuf.OptionOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -336,7 +336,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.TypeProto.internal_static_google_protobuf_Option_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -349,12 +349,12 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
       maybeForceBuilderInitialization();
     }
     private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3
+      if (com.google.protobuf.GeneratedMessageV3Internal
               .alwaysUseFieldBuilders) {
         getValueFieldBuilder();
       }
@@ -630,8 +630,8 @@ public Builder setNameBytes(
     }
 
     private com.google.protobuf.Any value_;
-    private com.google.protobuf.SingleFieldBuilderV3<
-        com.google.protobuf.Any, com.google.protobuf.Any.Builder, com.google.protobuf.AnyOrBuilder> valueBuilder_;
+    private SingleFieldBuilderV3Internal<
+            Any, Any.Builder, AnyOrBuilder> valueBuilder_;
     /**
      * <pre>
      * The option's value packed in an Any message. If the value is a primitive,
@@ -799,12 +799,12 @@ public com.google.protobuf.AnyOrBuilder getValueOrBuilder() {
      *
      * <code>.google.protobuf.Any value = 2;</code>
      */
-    private com.google.protobuf.SingleFieldBuilderV3<
-        com.google.protobuf.Any, com.google.protobuf.Any.Builder, com.google.protobuf.AnyOrBuilder> 
+    private SingleFieldBuilderV3Internal<
+            Any, Any.Builder, AnyOrBuilder>
         getValueFieldBuilder() {
       if (valueBuilder_ == null) {
-        valueBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-            com.google.protobuf.Any, com.google.protobuf.Any.Builder, com.google.protobuf.AnyOrBuilder>(
+        valueBuilder_ = new SingleFieldBuilderV3Internal<
+                    Any, Any.Builder, AnyOrBuilder>(
                 getValue(),
                 getParentForChildren(),
                 isClean());
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/OptionOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/OptionOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/OptionOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/OptionOrBuilder.java
diff --git a/protobuf-api/src/main/java/com/google/protobuf/RepeatedFieldBuilderV3Internal.java b/protobuf-api/src/main/java/com/google/protobuf/RepeatedFieldBuilderV3Internal.java
new file mode 100644
index 0000000..016085a
--- /dev/null
+++ b/protobuf-api/src/main/java/com/google/protobuf/RepeatedFieldBuilderV3Internal.java
@@ -0,0 +1,647 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+
+package com.google.protobuf;
+
+import static com.google.protobuf.Internal.checkNotNull;
+
+import java.util.AbstractList;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.RandomAccess;
+
+/**
+ * {@code RepeatedFieldBuilderV3} implements a structure that a protocol message uses to hold a
+ * repeated field of other protocol messages. It supports the classical use case of adding immutable
+ * {@link Message}'s to the repeated field and is highly optimized around this (no extra memory
+ * allocations and sharing of immutable arrays). <br>
+ * It also supports the additional use case of adding a {@link Message.Builder} to the repeated
+ * field and deferring conversion of that {@code Builder} to an immutable {@code Message}. In this
+ * way, it's possible to maintain a tree of {@code Builder}'s that acts as a fully read/write data
+ * structure. <br>
+ * Logically, one can think of a tree of builders as converting the entire tree to messages when
+ * build is called on the root or when any method is called that desires a Message instead of a
+ * Builder. In terms of the implementation, the {@code SingleFieldBuilderV3} and {@code
+ * RepeatedFieldBuilderV3} classes cache messages that were created so that messages only need to be
+ * created when some change occurred in its builder or a builder for one of its descendants.
+ *
+ * @param <MType> the type of message for the field
+ * @param <BType> the type of builder for the field
+ * @param <IType> the common interface for the message and the builder
+ * @author jonp@google.com (Jon Perlow)
+ */
+class RepeatedFieldBuilderV3Internal<
+        MType extends Message,
+        BType extends Message.Builder,
+        IType extends MessageOrBuilder>
+    implements Message.BuilderParent {
+
+  // Parent to send changes to.
+  private Message.BuilderParent parent;
+
+  // List of messages. Never null. It may be immutable, in which case
+  // isMessagesListMutable will be false. See note below.
+  private List<MType> messages;
+
+  // Whether messages is an mutable array that can be modified.
+  private boolean isMessagesListMutable;
+
+  // List of builders. May be null, in which case, no nested builders were
+  // created. If not null, entries represent the builder for that index.
+  private List<SingleFieldBuilderV3Internal<MType, BType, IType>> builders;
+
+  // Here are the invariants for messages and builders:
+  // 1. messages is never null and its count corresponds to the number of items
+  //    in the repeated field.
+  // 2. If builders is non-null, messages and builders MUST always
+  //    contain the same number of items.
+  // 3. Entries in either array can be null, but for any index, there MUST be
+  //    either a Message in messages or a builder in builders.
+  // 4. If the builder at an index is non-null, the builder is
+  //    authoritative. This is the case where a Builder was set on the index.
+  //    Any message in the messages array MUST be ignored.
+  // t. If the builder at an index is null, the message in the messages
+  //    list is authoritative. This is the case where a Message (not a Builder)
+  //    was set directly for an index.
+
+  // Indicates that we've built a message and so we are now obligated
+  // to dispatch dirty invalidations. See AbstractMessage.BuilderListener.
+  private boolean isClean;
+
+  // A view of this builder that exposes a List interface of messages. This is
+  // initialized on demand. This is fully backed by this object and all changes
+  // are reflected in it. Access to any item converts it to a message if it
+  // was a builder.
+  private MessageExternalList<MType, BType, IType> externalMessageList;
+
+  // A view of this builder that exposes a List interface of builders. This is
+  // initialized on demand. This is fully backed by this object and all changes
+  // are reflected in it. Access to any item converts it to a builder if it
+  // was a message.
+  private BuilderExternalList<MType, BType, IType> externalBuilderList;
+
+  // A view of this builder that exposes a List interface of the interface
+  // implemented by messages and builders. This is initialized on demand. This
+  // is fully backed by this object and all changes are reflected in it.
+  // Access to any item returns either a builder or message depending on
+  // what is most efficient.
+  private MessageOrBuilderExternalList<MType, BType, IType> externalMessageOrBuilderList;
+
+  /**
+   * Constructs a new builder with an empty list of messages.
+   *
+   * @param messages the current list of messages
+   * @param isMessagesListMutable Whether the messages list is mutable
+   * @param parent a listener to notify of changes
+   * @param isClean whether the builder is initially marked clean
+   */
+  public RepeatedFieldBuilderV3Internal(
+      List<MType> messages,
+      boolean isMessagesListMutable,
+      Message.BuilderParent parent,
+      boolean isClean) {
+    this.messages = messages;
+    this.isMessagesListMutable = isMessagesListMutable;
+    this.parent = parent;
+    this.isClean = isClean;
+  }
+
+  public void dispose() {
+    // Null out parent so we stop sending it invalidations.
+    parent = null;
+  }
+
+  /**
+   * Ensures that the list of messages is mutable so it can be updated. If it's immutable, a copy is
+   * made.
+   */
+  private void ensureMutableMessageList() {
+    if (!isMessagesListMutable) {
+      messages = new ArrayList<MType>(messages);
+      isMessagesListMutable = true;
+    }
+  }
+
+  /**
+   * Ensures that the list of builders is not null. If it's null, the list is created and
+   * initialized to be the same size as the messages list with null entries.
+   */
+  private void ensureBuilders() {
+    if (this.builders == null) {
+      this.builders = new ArrayList<SingleFieldBuilderV3Internal<MType, BType, IType>>(messages.size());
+      for (int i = 0; i < messages.size(); i++) {
+        builders.add(null);
+      }
+    }
+  }
+
+  /**
+   * Gets the count of items in the list.
+   *
+   * @return the count of items in the list.
+   */
+  public int getCount() {
+    return messages.size();
+  }
+
+  /**
+   * Gets whether the list is empty.
+   *
+   * @return whether the list is empty
+   */
+  public boolean isEmpty() {
+    return messages.isEmpty();
+  }
+
+  /**
+   * Get the message at the specified index. If the message is currently stored as a {@code
+   * Builder}, it is converted to a {@code Message} by calling {@link Message.Builder#buildPartial}
+   * on it.
+   *
+   * @param index the index of the message to get
+   * @return the message for the specified index
+   */
+  public MType getMessage(int index) {
+    return getMessage(index, false);
+  }
+
+  /**
+   * Get the message at the specified index. If the message is currently stored as a {@code
+   * Builder}, it is converted to a {@code Message} by calling {@link Message.Builder#buildPartial}
+   * on it.
+   *
+   * @param index the index of the message to get
+   * @param forBuild this is being called for build so we want to make sure we
+   *     SingleFieldBuilderV3.build to send dirty invalidations
+   * @return the message for the specified index
+   */
+  private MType getMessage(int index, boolean forBuild) {
+    if (this.builders == null) {
+      // We don't have any builders -- return the current Message.
+      // This is the case where no builder was created, so we MUST have a
+      // Message.
+      return messages.get(index);
+    }
+
+    SingleFieldBuilderV3Internal<MType, BType, IType> builder = builders.get(index);
+    if (builder == null) {
+      // We don't have a builder -- return the current message.
+      // This is the case where no builder was created for the entry at index,
+      // so we MUST have a message.
+      return messages.get(index);
+
+    } else {
+      return forBuild ? builder.build() : builder.getMessage();
+    }
+  }
+
+  /**
+   * Gets a builder for the specified index. If no builder has been created for that index, a
+   * builder is created on demand by calling {@link Message#toBuilder}.
+   *
+   * @param index the index of the message to get
+   * @return The builder for that index
+   */
+  public BType getBuilder(int index) {
+    ensureBuilders();
+    SingleFieldBuilderV3Internal<MType, BType, IType> builder = builders.get(index);
+    if (builder == null) {
+      MType message = messages.get(index);
+      builder = new SingleFieldBuilderV3Internal<MType, BType, IType>(message, this, isClean);
+      builders.set(index, builder);
+    }
+    return builder.getBuilder();
+  }
+
+  /**
+   * Gets the base class interface for the specified index. This may either be a builder or a
+   * message. It will return whatever is more efficient.
+   *
+   * @param index the index of the message to get
+   * @return the message or builder for the index as the base class interface
+   */
+  @SuppressWarnings("unchecked")
+  public IType getMessageOrBuilder(int index) {
+    if (this.builders == null) {
+      // We don't have any builders -- return the current Message.
+      // This is the case where no builder was created, so we MUST have a
+      // Message.
+      return (IType) messages.get(index);
+    }
+
+    SingleFieldBuilderV3Internal<MType, BType, IType> builder = builders.get(index);
+    if (builder == null) {
+      // We don't have a builder -- return the current message.
+      // This is the case where no builder was created for the entry at index,
+      // so we MUST have a message.
+      return (IType) messages.get(index);
+
+    } else {
+      return builder.getMessageOrBuilder();
+    }
+  }
+
+  /**
+   * Sets a message at the specified index replacing the existing item at that index.
+   *
+   * @param index the index to set.
+   * @param message the message to set
+   * @return the builder
+   */
+  @CanIgnoreReturnValue
+  public RepeatedFieldBuilderV3Internal<MType, BType, IType> setMessage(int index, MType message) {
+    checkNotNull(message);
+    ensureMutableMessageList();
+    messages.set(index, message);
+    if (builders != null) {
+      SingleFieldBuilderV3Internal<MType, BType, IType> entry = builders.set(index, null);
+      if (entry != null) {
+        entry.dispose();
+      }
+    }
+    onChanged();
+    incrementModCounts();
+    return this;
+  }
+
+  /**
+   * Appends the specified element to the end of this list.
+   *
+   * @param message the message to add
+   * @return the builder
+   */
+  @CanIgnoreReturnValue
+  public RepeatedFieldBuilderV3Internal<MType, BType, IType> addMessage(MType message) {
+    checkNotNull(message);
+    ensureMutableMessageList();
+    messages.add(message);
+    if (builders != null) {
+      builders.add(null);
+    }
+    onChanged();
+    incrementModCounts();
+    return this;
+  }
+
+  /**
+   * Inserts the specified message at the specified position in this list. Shifts the element
+   * currently at that position (if any) and any subsequent elements to the right (adds one to their
+   * indices).
+   *
+   * @param index the index at which to insert the message
+   * @param message the message to add
+   * @return the builder
+   */
+  @CanIgnoreReturnValue
+  public RepeatedFieldBuilderV3Internal<MType, BType, IType> addMessage(int index, MType message) {
+    checkNotNull(message);
+    ensureMutableMessageList();
+    messages.add(index, message);
+    if (builders != null) {
+      builders.add(index, null);
+    }
+    onChanged();
+    incrementModCounts();
+    return this;
+  }
+
+  /**
+   * Appends all of the messages in the specified collection to the end of this list, in the order
+   * that they are returned by the specified collection's iterator.
+   *
+   * @param values the messages to add
+   * @return the builder
+   */
+  @CanIgnoreReturnValue
+  public RepeatedFieldBuilderV3Internal<MType, BType, IType> addAllMessages(
+      Iterable<? extends MType> values) {
+    for (final MType value : values) {
+      checkNotNull(value);
+    }
+
+    // If we can inspect the size, we can more efficiently add messages.
+    int size = -1;
+    if (values instanceof Collection) {
+      final Collection<?> collection = (Collection<?>) values;
+      if (collection.isEmpty()) {
+        return this;
+      }
+      size = collection.size();
+    }
+    ensureMutableMessageList();
+
+    if (size >= 0 && messages instanceof ArrayList) {
+      ((ArrayList<MType>) messages).ensureCapacity(messages.size() + size);
+    }
+
+    for (MType value : values) {
+      addMessage(value);
+    }
+
+    onChanged();
+    incrementModCounts();
+    return this;
+  }
+
+  /**
+   * Appends a new builder to the end of this list and returns the builder.
+   *
+   * @param message the message to add which is the basis of the builder
+   * @return the new builder
+   */
+  public BType addBuilder(MType message) {
+    ensureMutableMessageList();
+    ensureBuilders();
+    SingleFieldBuilderV3Internal<MType, BType, IType> builder =
+        new SingleFieldBuilderV3Internal<MType, BType, IType>(message, this, isClean);
+    messages.add(null);
+    builders.add(builder);
+    onChanged();
+    incrementModCounts();
+    return builder.getBuilder();
+  }
+
+  /**
+   * Inserts a new builder at the specified position in this list. Shifts the element currently at
+   * that position (if any) and any subsequent elements to the right (adds one to their indices).
+   *
+   * @param index the index at which to insert the builder
+   * @param message the message to add which is the basis of the builder
+   * @return the builder
+   */
+  public BType addBuilder(int index, MType message) {
+    ensureMutableMessageList();
+    ensureBuilders();
+    SingleFieldBuilderV3Internal<MType, BType, IType> builder =
+        new SingleFieldBuilderV3Internal<MType, BType, IType>(message, this, isClean);
+    messages.add(index, null);
+    builders.add(index, builder);
+    onChanged();
+    incrementModCounts();
+    return builder.getBuilder();
+  }
+
+  /**
+   * Removes the element at the specified position in this list. Shifts any subsequent elements to
+   * the left (subtracts one from their indices).
+   *
+   * @param index the index at which to remove the message
+   */
+  public void remove(int index) {
+    ensureMutableMessageList();
+    messages.remove(index);
+    if (builders != null) {
+      SingleFieldBuilderV3Internal<MType, BType, IType> entry = builders.remove(index);
+      if (entry != null) {
+        entry.dispose();
+      }
+    }
+    onChanged();
+    incrementModCounts();
+  }
+
+  /** Removes all of the elements from this list. The list will be empty after this call returns. */
+  public void clear() {
+    messages = Collections.emptyList();
+    isMessagesListMutable = false;
+    if (builders != null) {
+      for (SingleFieldBuilderV3Internal<MType, BType, IType> entry : builders) {
+        if (entry != null) {
+          entry.dispose();
+        }
+      }
+      builders = null;
+    }
+    onChanged();
+    incrementModCounts();
+  }
+
+  /**
+   * Builds the list of messages from the builder and returns them.
+   *
+   * @return an immutable list of messages
+   */
+  public List<MType> build() {
+    // Now that build has been called, we are required to dispatch
+    // invalidations.
+    isClean = true;
+
+    if (!isMessagesListMutable && builders == null) {
+      // We still have an immutable list and we never created a builder.
+      return messages;
+    }
+
+    boolean allMessagesInSync = true;
+    if (!isMessagesListMutable) {
+      // We still have an immutable list. Let's see if any of them are out
+      // of sync with their builders.
+      for (int i = 0; i < messages.size(); i++) {
+        Message message = messages.get(i);
+        SingleFieldBuilderV3Internal<MType, BType, IType> builder = builders.get(i);
+        if (builder != null) {
+          if (builder.build() != message) {
+            allMessagesInSync = false;
+            break;
+          }
+        }
+      }
+      if (allMessagesInSync) {
+        // Immutable list is still in sync.
+        return messages;
+      }
+    }
+
+    // Need to make sure messages is up to date
+    ensureMutableMessageList();
+    for (int i = 0; i < messages.size(); i++) {
+      messages.set(i, getMessage(i, true));
+    }
+
+    // We're going to return our list as immutable so we mark that we can
+    // no longer update it.
+    messages = Collections.unmodifiableList(messages);
+    isMessagesListMutable = false;
+    return messages;
+  }
+
+  /**
+   * Gets a view of the builder as a list of messages. The returned list is live and will reflect
+   * any changes to the underlying builder.
+   *
+   * @return the messages in the list
+   */
+  public List<MType> getMessageList() {
+    if (externalMessageList == null) {
+      externalMessageList = new MessageExternalList<MType, BType, IType>(this);
+    }
+    return externalMessageList;
+  }
+
+  /**
+   * Gets a view of the builder as a list of builders. This returned list is live and will reflect
+   * any changes to the underlying builder.
+   *
+   * @return the builders in the list
+   */
+  public List<BType> getBuilderList() {
+    if (externalBuilderList == null) {
+      externalBuilderList = new BuilderExternalList<MType, BType, IType>(this);
+    }
+    return externalBuilderList;
+  }
+
+  /**
+   * Gets a view of the builder as a list of MessageOrBuilders. This returned list is live and will
+   * reflect any changes to the underlying builder.
+   *
+   * @return the builders in the list
+   */
+  public List<IType> getMessageOrBuilderList() {
+    if (externalMessageOrBuilderList == null) {
+      externalMessageOrBuilderList = new MessageOrBuilderExternalList<MType, BType, IType>(this);
+    }
+    return externalMessageOrBuilderList;
+  }
+
+  /**
+   * Called when a the builder or one of its nested children has changed and any parent should be
+   * notified of its invalidation.
+   */
+  private void onChanged() {
+    if (isClean && parent != null) {
+      parent.markDirty();
+
+      // Don't keep dispatching invalidations until build is called again.
+      isClean = false;
+    }
+  }
+
+  @Override
+  public void markDirty() {
+    onChanged();
+  }
+
+  /**
+   * Increments the mod counts so that an ConcurrentModificationException can be thrown if calling
+   * code tries to modify the builder while its iterating the list.
+   */
+  private void incrementModCounts() {
+    if (externalMessageList != null) {
+      externalMessageList.incrementModCount();
+    }
+    if (externalBuilderList != null) {
+      externalBuilderList.incrementModCount();
+    }
+    if (externalMessageOrBuilderList != null) {
+      externalMessageOrBuilderList.incrementModCount();
+    }
+  }
+
+  /**
+   * Provides a live view of the builder as a list of messages.
+   *
+   * @param <MType> the type of message for the field
+   * @param <BType> the type of builder for the field
+   * @param <IType> the common interface for the message and the builder
+   */
+  private static class MessageExternalList<
+          MType extends Message,
+          BType extends Message.Builder,
+          IType extends MessageOrBuilder>
+      extends AbstractList<MType> implements List<MType>, RandomAccess {
+
+    RepeatedFieldBuilderV3Internal<MType, BType, IType> builder;
+
+    MessageExternalList(RepeatedFieldBuilderV3Internal<MType, BType, IType> builder) {
+      this.builder = builder;
+    }
+
+    @Override
+    public int size() {
+      return this.builder.getCount();
+    }
+
+    @Override
+    public MType get(int index) {
+      return builder.getMessage(index);
+    }
+
+    void incrementModCount() {
+      modCount++;
+    }
+  }
+
+  /**
+   * Provides a live view of the builder as a list of builders.
+   *
+   * @param <MType> the type of message for the field
+   * @param <BType> the type of builder for the field
+   * @param <IType> the common interface for the message and the builder
+   */
+  private static class BuilderExternalList<
+          MType extends Message,
+          BType extends Message.Builder,
+          IType extends MessageOrBuilder>
+      extends AbstractList<BType> implements List<BType>, RandomAccess {
+
+    RepeatedFieldBuilderV3Internal<MType, BType, IType> builder;
+
+    BuilderExternalList(RepeatedFieldBuilderV3Internal<MType, BType, IType> builder) {
+      this.builder = builder;
+    }
+
+    @Override
+    public int size() {
+      return this.builder.getCount();
+    }
+
+    @Override
+    public BType get(int index) {
+      return builder.getBuilder(index);
+    }
+
+    void incrementModCount() {
+      modCount++;
+    }
+  }
+
+  /**
+   * Provides a live view of the builder as a list of builders.
+   *
+   * @param <MType> the type of message for the field
+   * @param <BType> the type of builder for the field
+   * @param <IType> the common interface for the message and the builder
+   */
+  private static class MessageOrBuilderExternalList<
+          MType extends Message,
+          BType extends Message.Builder,
+          IType extends MessageOrBuilder>
+      extends AbstractList<IType> implements List<IType>, RandomAccess {
+
+    RepeatedFieldBuilderV3Internal<MType, BType, IType> builder;
+
+    MessageOrBuilderExternalList(RepeatedFieldBuilderV3Internal<MType, BType, IType> builder) {
+      this.builder = builder;
+    }
+
+    @Override
+    public int size() {
+      return this.builder.getCount();
+    }
+
+    @Override
+    public IType get(int index) {
+      return builder.getMessageOrBuilder(index);
+    }
+
+    void incrementModCount() {
+      modCount++;
+    }
+  }
+}
diff --git a/protobuf-api/src/main/java/com/google/protobuf/SerializedForm.java b/protobuf-api/src/main/java/com/google/protobuf/SerializedForm.java
new file mode 100644
index 0000000..78b40de
--- /dev/null
+++ b/protobuf-api/src/main/java/com/google/protobuf/SerializedForm.java
@@ -0,0 +1,91 @@
+package com.google.protobuf;
+
+import java.io.ObjectStreamException;
+import java.io.Serializable;
+
+/**
+ * A serialized (serializable) form of the generated message. Stores the message as a class name
+ * and a byte array.
+ */
+final class SerializedForm implements Serializable {
+
+    public static SerializedForm of(MessageLite message) {
+        return new SerializedForm(message);
+    }
+
+    private static final long serialVersionUID = 0L;
+
+    // since v3.6.1
+    private final Class<?> messageClass;
+    private final String messageClassName;
+    private final byte[] asBytes;
+
+    /**
+     * Creates the serialized form by calling {@link com.google.protobuf.MessageLite#toByteArray}.
+     *
+     * @param regularForm the message to serialize
+     */
+    SerializedForm(MessageLite regularForm) {
+        messageClass = regularForm.getClass();
+        messageClassName = regularForm.getClass().getName();
+        asBytes = regularForm.toByteArray();
+    }
+
+    /**
+     * When read from an ObjectInputStream, this method converts this object back to the regular
+     * form. Part of Java's serialization magic.
+     *
+     * @return a GeneratedMessage of the type that was serialized
+     */
+    protected Object readResolve() throws ObjectStreamException {
+        try {
+            Class<?> messageClass = resolveMessageClass();
+            java.lang.reflect.Field defaultInstanceField =
+                    messageClass.getDeclaredField("DEFAULT_INSTANCE");
+            defaultInstanceField.setAccessible(true);
+            MessageLite defaultInstance = (MessageLite) defaultInstanceField.get(null);
+            return defaultInstance.newBuilderForType().mergeFrom(asBytes).buildPartial();
+        } catch (ClassNotFoundException e) {
+            throw new RuntimeException("Unable to find proto buffer class: " + messageClassName, e);
+        } catch (NoSuchFieldException e) {
+            return readResolveFallback();
+        } catch (SecurityException e) {
+            throw new RuntimeException("Unable to call DEFAULT_INSTANCE in " + messageClassName, e);
+        } catch (IllegalAccessException e) {
+            throw new RuntimeException("Unable to call parsePartialFrom", e);
+        } catch (InvalidProtocolBufferException e) {
+            throw new RuntimeException("Unable to understand proto buffer", e);
+        }
+    }
+
+    /**
+     * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1 generated code.
+     */
+    @Deprecated
+    private Object readResolveFallback() throws ObjectStreamException {
+        try {
+            Class<?> messageClass = resolveMessageClass();
+            java.lang.reflect.Field defaultInstanceField =
+                    messageClass.getDeclaredField("defaultInstance");
+            defaultInstanceField.setAccessible(true);
+            MessageLite defaultInstance = (MessageLite) defaultInstanceField.get(null);
+            return defaultInstance.newBuilderForType()
+                    .mergeFrom(asBytes)
+                    .buildPartial();
+        } catch (ClassNotFoundException e) {
+            throw new RuntimeException("Unable to find proto buffer class: " + messageClassName, e);
+        } catch (NoSuchFieldException e) {
+            throw new RuntimeException("Unable to find defaultInstance in " + messageClassName, e);
+        } catch (SecurityException e) {
+            throw new RuntimeException("Unable to call defaultInstance in " + messageClassName, e);
+        } catch (IllegalAccessException e) {
+            throw new RuntimeException("Unable to call parsePartialFrom", e);
+        } catch (InvalidProtocolBufferException e) {
+            throw new RuntimeException("Unable to understand proto buffer", e);
+        }
+    }
+
+    private Class<?> resolveMessageClass() throws ClassNotFoundException {
+        return messageClass != null ? messageClass : Class.forName(messageClassName);
+    }
+}
\ No newline at end of file
diff --git a/protobuf-api/src/main/java/com/google/protobuf/SingleFieldBuilderV3Internal.java b/protobuf-api/src/main/java/com/google/protobuf/SingleFieldBuilderV3Internal.java
new file mode 100644
index 0000000..49a44f6
--- /dev/null
+++ b/protobuf-api/src/main/java/com/google/protobuf/SingleFieldBuilderV3Internal.java
@@ -0,0 +1,217 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+
+package com.google.protobuf;
+
+import static com.google.protobuf.Internal.checkNotNull;
+
+/**
+ * {@code SingleFieldBuilderV3} implements a structure that a protocol message uses to hold a single
+ * field of another protocol message. It supports the classical use case of setting an immutable
+ * {@link Message} as the value of the field and is highly optimized around this.
+ *
+ * <p>It also supports the additional use case of setting a {@link Message.Builder} as the field and
+ * deferring conversion of that {@code Builder} to an immutable {@code Message}. In this way, it's
+ * possible to maintain a tree of {@code Builder}'s that acts as a fully read/write data structure.
+ * <br>
+ * Logically, one can think of a tree of builders as converting the entire tree to messages when
+ * build is called on the root or when any method is called that desires a Message instead of a
+ * Builder. In terms of the implementation, the {@code SingleFieldBuilderV3} and {@code
+ * RepeatedFieldBuilderV3} classes cache messages that were created so that messages only need to be
+ * created when some change occurred in its builder or a builder for one of its descendants.
+ *
+ * @param <MType> the type of message for the field
+ * @param <BType> the type of builder for the field
+ * @param <IType> the common interface for the message and the builder
+ * @author jonp@google.com (Jon Perlow)
+ */
+class SingleFieldBuilderV3Internal<
+        MType extends Message,
+        BType extends Message.Builder,
+        IType extends MessageOrBuilder>
+    implements Message.BuilderParent {
+
+  // Parent to send changes to.
+  private Message.BuilderParent parent;
+
+  // Invariant: one of builder or message fields must be non-null.
+
+  // If set, this is the case where we are backed by a builder. In this case,
+  // message field represents a cached message for the builder (or null if
+  // there is no cached message).
+  private BType builder;
+
+  // If builder is non-null, this represents a cached message from the builder.
+  // If builder is null, this is the authoritative message for the field.
+  private MType message;
+
+  // Indicates that we've built a message and so we are now obligated
+  // to dispatch dirty invalidations. See AbstractMessage.BuilderListener.
+  private boolean isClean;
+
+  public SingleFieldBuilderV3Internal(MType message, Message.BuilderParent parent, boolean isClean) {
+    this.message = checkNotNull(message);
+    this.parent = parent;
+    this.isClean = isClean;
+  }
+
+  public void dispose() {
+    // Null out parent so we stop sending it invalidations.
+    parent = null;
+  }
+
+  /**
+   * Get the message for the field. If the message is currently stored as a {@code Builder}, it is
+   * converted to a {@code Message} by calling {@link Message.Builder#buildPartial} on it. If no
+   * message has been set, returns the default instance of the message.
+   *
+   * @return the message for the field
+   */
+  @SuppressWarnings("unchecked")
+  public MType getMessage() {
+    if (message == null) {
+      // If message is null, the invariant is that we must be have a builder.
+      message = (MType) builder.buildPartial();
+    }
+    return message;
+  }
+
+  /**
+   * Builds the message and returns it.
+   *
+   * @return the message
+   */
+  public MType build() {
+    // Now that build has been called, we are required to dispatch
+    // invalidations.
+    isClean = true;
+    return getMessage();
+  }
+
+  /**
+   * Gets a builder for the field. If no builder has been created yet, a builder is created on
+   * demand by calling {@link Message#toBuilder}.
+   *
+   * @return The builder for the field
+   */
+  @SuppressWarnings("unchecked")
+  public BType getBuilder() {
+    if (builder == null) {
+      // builder.mergeFrom() on a fresh builder
+      // does not create any sub-objects with independent clean/dirty states,
+      // therefore setting the builder itself to clean without actually calling
+      // build() cannot break any invariants.
+      builder = (BType) message.newBuilderForType();
+      builder.mergeFrom(message); // no-op if message is the default message
+//      builder.markClean();
+    }
+    return builder;
+  }
+
+  /**
+   * Gets the base class interface for the field. This may either be a builder or a message. It will
+   * return whatever is more efficient.
+   *
+   * @return the message or builder for the field as the base class interface
+   */
+  @SuppressWarnings("unchecked")
+  public IType getMessageOrBuilder() {
+    if (builder != null) {
+      return (IType) builder;
+    } else {
+      return (IType) message;
+    }
+  }
+
+  /**
+   * Sets a message for the field replacing any existing value.
+   *
+   * @param message the message to set
+   * @return the builder
+   */
+  @CanIgnoreReturnValue
+  public SingleFieldBuilderV3Internal<MType, BType, IType> setMessage(MType message) {
+    this.message = checkNotNull(message);
+    if (builder != null) {
+//      builder.dispose();
+      builder = null;
+    }
+    onChanged();
+    return this;
+  }
+
+  /**
+   * Merges the field from another field.
+   *
+   * @param value the value to merge from
+   * @return the builder
+   */
+  @CanIgnoreReturnValue
+  public SingleFieldBuilderV3Internal<MType, BType, IType> mergeFrom(MType value) {
+    if (builder == null && message == message.getDefaultInstanceForType()) {
+      message = value;
+    } else {
+      getBuilder().mergeFrom(value);
+    }
+    onChanged();
+    return this;
+  }
+
+  /**
+   * Clears the value of the field.
+   *
+   * @return the builder
+   */
+  @SuppressWarnings("unchecked")
+  @CanIgnoreReturnValue
+  public SingleFieldBuilderV3Internal<MType, BType, IType> clear() {
+    message =
+        (MType)
+            (message != null
+                ? message.getDefaultInstanceForType()
+                : builder.getDefaultInstanceForType());
+    if (builder != null) {
+//      builder.dispose();
+      builder = null;
+    }
+    onChanged();
+    // After clearing, parent is dirty, but this field builder is now clean and any changes should
+    // trickle up.
+    isClean = true;
+    return this;
+  }
+
+  /**
+   * Called when a the builder or one of its nested children has changed and any parent should be
+   * notified of its invalidation.
+   */
+  private void onChanged() {
+    // If builder is null, this is the case where onChanged is being called
+    // from setMessage or clear.
+    if (builder != null) {
+      message = null;
+    }
+    if (isClean && parent != null) {
+      parent.markDirty();
+
+      // Don't keep dispatching invalidations until build is called again.
+      isClean = false;
+    }
+  }
+
+  static <T> T checkNotNull(T obj) {
+    if (obj == null) {
+      throw new NullPointerException();
+    }
+    return obj;
+  }
+  
+  @Override
+  public void markDirty() {
+    onChanged();
+  }
+}
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/SourceContext.java b/protobuf-api/src/main/java/com/google/protobuf/SourceContext.java
similarity index 93%
rename from protobuf-sdk/src/main/java/com/google/protobuf/SourceContext.java
rename to protobuf-api/src/main/java/com/google/protobuf/SourceContext.java
index 38c29b8..059b3ec 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/SourceContext.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/SourceContext.java
@@ -13,12 +13,12 @@
  * Protobuf type {@code google.protobuf.SourceContext}
  */
 public final class SourceContext extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.FlattenedGeneratedMessageV3 implements
     // @@protoc_insertion_point(message_implements:google.protobuf.SourceContext)
     SourceContextOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use SourceContext.newBuilder() to construct.
-  private SourceContext(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private SourceContext(com.google.protobuf.FlattenedGeneratedMessageV3.Builder<?> builder) {
     super(builder);
   }
   private SourceContext() {
@@ -38,7 +38,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.FlattenedGeneratedMessageV3.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.SourceContextProto.internal_static_google_protobuf_SourceContext_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -108,8 +108,8 @@ public final boolean isInitialized() {
   @java.lang.Override
   public void writeTo(com.google.protobuf.CodedOutputStream output)
                       throws java.io.IOException {
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(fileName_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 1, fileName_);
+    if (!com.google.protobuf.FlattenedGeneratedMessageV3.isStringEmpty(fileName_)) {
+      com.google.protobuf.FlattenedGeneratedMessageV3.writeString(output, 1, fileName_);
     }
     getUnknownFields().writeTo(output);
   }
@@ -120,8 +120,8 @@ public int getSerializedSize() {
     if (size != -1) return size;
 
     size = 0;
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(fileName_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, fileName_);
+    if (!com.google.protobuf.FlattenedGeneratedMessageV3.isStringEmpty(fileName_)) {
+      size += com.google.protobuf.FlattenedGeneratedMessageV3.computeStringSize(1, fileName_);
     }
     size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
@@ -192,20 +192,20 @@ public static com.google.protobuf.SourceContext parseFrom(
   }
   public static com.google.protobuf.SourceContext parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.FlattenedGeneratedMessageV3
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.SourceContext parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.FlattenedGeneratedMessageV3
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.SourceContext parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.FlattenedGeneratedMessageV3
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -213,20 +213,20 @@ public static com.google.protobuf.SourceContext parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.FlattenedGeneratedMessageV3
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.SourceContext parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.FlattenedGeneratedMessageV3
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.SourceContext parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.FlattenedGeneratedMessageV3
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -246,7 +246,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.FlattenedGeneratedMessageV3.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -259,7 +259,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.SourceContext}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.FlattenedGeneratedMessageV3.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.SourceContext)
       com.google.protobuf.SourceContextOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -268,7 +268,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.FlattenedGeneratedMessageV3.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.SourceContextProto.internal_static_google_protobuf_SourceContext_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -281,7 +281,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.FlattenedGeneratedMessageV3.BuilderParent parent) {
       super(parent);
 
     }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/SourceContextOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/SourceContextOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/SourceContextOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/SourceContextOrBuilder.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/SourceContextProto.java b/protobuf-api/src/main/java/com/google/protobuf/SourceContextProto.java
similarity index 93%
rename from protobuf-sdk/src/main/java/com/google/protobuf/SourceContextProto.java
rename to protobuf-api/src/main/java/com/google/protobuf/SourceContextProto.java
index 0fdadc4..e8aa94d 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/SourceContextProto.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/SourceContextProto.java
@@ -18,7 +18,7 @@ public static void registerAllExtensions(
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_SourceContext_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.FlattenedGeneratedMessageV3.FieldAccessorTable
       internal_static_google_protobuf_SourceContext_fieldAccessorTable;
 
   public static com.google.protobuf.Descriptors.FileDescriptor
@@ -43,7 +43,7 @@ public static void registerAllExtensions(
     internal_static_google_protobuf_SourceContext_descriptor =
       getDescriptor().getMessageTypes().get(0);
     internal_static_google_protobuf_SourceContext_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.FlattenedGeneratedMessageV3.FieldAccessorTable(
         internal_static_google_protobuf_SourceContext_descriptor,
         new java.lang.String[] { "FileName", });
   }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/StringValue.java b/protobuf-api/src/main/java/com/google/protobuf/StringValue.java
similarity index 93%
rename from protobuf-sdk/src/main/java/com/google/protobuf/StringValue.java
rename to protobuf-api/src/main/java/com/google/protobuf/StringValue.java
index c5ef53e..d9d3615 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/StringValue.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/StringValue.java
@@ -14,12 +14,12 @@
  * Protobuf type {@code google.protobuf.StringValue}
  */
 public final class StringValue extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.StringValue)
     StringValueOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use StringValue.newBuilder() to construct.
-  private StringValue(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private StringValue(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private StringValue() {
@@ -39,7 +39,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.WrappersProto.internal_static_google_protobuf_StringValue_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -107,8 +107,8 @@ public final boolean isInitialized() {
   @java.lang.Override
   public void writeTo(com.google.protobuf.CodedOutputStream output)
                       throws java.io.IOException {
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(value_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 1, value_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(value_)) {
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, value_);
     }
     getUnknownFields().writeTo(output);
   }
@@ -119,8 +119,8 @@ public int getSerializedSize() {
     if (size != -1) return size;
 
     size = 0;
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(value_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, value_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(value_)) {
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(1, value_);
     }
     size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
@@ -191,20 +191,20 @@ public static com.google.protobuf.StringValue parseFrom(
   }
   public static com.google.protobuf.StringValue parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.StringValue parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.StringValue parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -212,20 +212,20 @@ public static com.google.protobuf.StringValue parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.StringValue parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.StringValue parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -245,7 +245,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -259,7 +259,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.StringValue}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.StringValue)
       com.google.protobuf.StringValueOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -268,7 +268,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.WrappersProto.internal_static_google_protobuf_StringValue_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -281,7 +281,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/StringValueOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/StringValueOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/StringValueOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/StringValueOrBuilder.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/Struct.java b/protobuf-api/src/main/java/com/google/protobuf/Struct.java
similarity index 96%
rename from protobuf-sdk/src/main/java/com/google/protobuf/Struct.java
rename to protobuf-api/src/main/java/com/google/protobuf/Struct.java
index 886142c..387e27b 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/Struct.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/Struct.java
@@ -19,12 +19,12 @@
  * Protobuf type {@code google.protobuf.Struct}
  */
 public final class Struct extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.Struct)
     StructOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use Struct.newBuilder() to construct.
-  private Struct(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private Struct(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private Struct() {
@@ -55,7 +55,7 @@ protected com.google.protobuf.MapFieldReflectionAccessor internalGetMapFieldRefl
     }
   }
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.StructProto.internal_static_google_protobuf_Struct_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -171,7 +171,7 @@ public final boolean isInitialized() {
   @java.lang.Override
   public void writeTo(com.google.protobuf.CodedOutputStream output)
                       throws java.io.IOException {
-    com.google.protobuf.GeneratedMessageV3
+    com.google.protobuf.GeneratedMessageV3Internal
       .serializeStringMapTo(
         output,
         internalGetFields(),
@@ -267,20 +267,20 @@ public static com.google.protobuf.Struct parseFrom(
   }
   public static com.google.protobuf.Struct parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Struct parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.Struct parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -288,20 +288,20 @@ public static com.google.protobuf.Struct parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.Struct parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Struct parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -321,7 +321,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -340,7 +340,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.Struct}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.Struct)
       com.google.protobuf.StructOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -371,7 +371,7 @@ protected com.google.protobuf.MapFieldReflectionAccessor internalGetMutableMapFi
       }
     }
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.StructProto.internal_static_google_protobuf_Struct_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -384,7 +384,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/StructOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/StructOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/StructOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/StructOrBuilder.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/StructProto.java b/protobuf-api/src/main/java/com/google/protobuf/StructProto.java
similarity index 88%
rename from protobuf-sdk/src/main/java/com/google/protobuf/StructProto.java
rename to protobuf-api/src/main/java/com/google/protobuf/StructProto.java
index 5f0050f..42bb4dd 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/StructProto.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/StructProto.java
@@ -18,22 +18,22 @@ public static void registerAllExtensions(
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_Struct_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_Struct_fieldAccessorTable;
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_Struct_FieldsEntry_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_Struct_FieldsEntry_fieldAccessorTable;
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_Value_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_Value_fieldAccessorTable;
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_ListValue_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_ListValue_fieldAccessorTable;
 
   public static com.google.protobuf.Descriptors.FileDescriptor
@@ -68,25 +68,25 @@ public static void registerAllExtensions(
     internal_static_google_protobuf_Struct_descriptor =
       getDescriptor().getMessageTypes().get(0);
     internal_static_google_protobuf_Struct_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_Struct_descriptor,
         new java.lang.String[] { "Fields", });
     internal_static_google_protobuf_Struct_FieldsEntry_descriptor =
       internal_static_google_protobuf_Struct_descriptor.getNestedTypes().get(0);
     internal_static_google_protobuf_Struct_FieldsEntry_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_Struct_FieldsEntry_descriptor,
         new java.lang.String[] { "Key", "Value", });
     internal_static_google_protobuf_Value_descriptor =
       getDescriptor().getMessageTypes().get(1);
     internal_static_google_protobuf_Value_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_Value_descriptor,
         new java.lang.String[] { "NullValue", "NumberValue", "StringValue", "BoolValue", "StructValue", "ListValue", "Kind", });
     internal_static_google_protobuf_ListValue_descriptor =
       getDescriptor().getMessageTypes().get(2);
     internal_static_google_protobuf_ListValue_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_ListValue_descriptor,
         new java.lang.String[] { "Values", });
   }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/Syntax.java b/protobuf-api/src/main/java/com/google/protobuf/Syntax.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/Syntax.java
rename to protobuf-api/src/main/java/com/google/protobuf/Syntax.java
diff --git a/protobuf-api/src/main/java/com/google/protobuf/TextFormatEscaper.java b/protobuf-api/src/main/java/com/google/protobuf/TextFormatEscaper.java
index 8e43fb0..772700c 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/TextFormatEscaper.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/TextFormatEscaper.java
@@ -7,6 +7,8 @@
 
 package com.google.protobuf;
 
+import java.io.IOException;
+
 /**
  * Provide text format escaping of proto instances. These ASCII characters are escaped:
  *
@@ -25,7 +27,7 @@
  * Other ASCII characters less than 32 and all Unicode characters 128 or greater are
  * first encoded as UTF-8, then each byte is escaped individually as a 3-digit octal escape.
  */
-final class TextFormatEscaper {
+public final class TextFormatEscaper {
   private TextFormatEscaper() {}
 
   private interface ByteSequence {
@@ -37,7 +39,7 @@ private interface ByteSequence {
   /**
    * Backslash escapes bytes in the format used in protocol buffer text format.
    */
-  static String escapeBytes(ByteSequence input) {
+  public static String escapeBytes(ByteSequence input) {
     final StringBuilder builder = new StringBuilder(input.size());
     for (int i = 0; i < input.size(); i++) {
       byte b = input.byteAt(i);
@@ -126,12 +128,222 @@ public byte byteAt(int offset) {
   /**
    * Like {@link #escapeBytes(ByteString)}, but escapes a text string.
    */
-  static String escapeText(String input) {
+  public static String escapeText(String input) {
     return escapeBytes(ByteString.copyFromUtf8(input));
   }
 
   /** Escape double quotes and backslashes in a String for unicode output of a message. */
-  static String escapeDoubleQuotesAndBackslashes(String input) {
+  public static String escapeDoubleQuotesAndBackslashes(String input) {
     return input.replace("\\", "\\\\").replace("\"", "\\\"");
   }
+
+  /** Is this an octal digit? */
+  private static boolean isOctal(final byte c) {
+    return '0' <= c && c <= '7';
+  }
+
+  /** Is this a hex digit? */
+  private static boolean isHex(final byte c) {
+    return ('0' <= c && c <= '9') || ('a' <= c && c <= 'f') || ('A' <= c && c <= 'F');
+  }
+
+  /**
+   * Interpret a character as a digit (in any base up to 36) and return the numeric value. This is
+   * like {@code Character.digit()} but we don't accept non-ASCII digits.
+   */
+  private static int digitValue(final byte c) {
+    if ('0' <= c && c <= '9') {
+      return c - '0';
+    } else if ('a' <= c && c <= 'z') {
+      return c - 'a' + 10;
+    } else {
+      return c - 'A' + 10;
+    }
+  }
+
+  /**
+   * Thrown by {@link TextFormat#unescapeBytes} and {@link TextFormat#unescapeText} when an invalid
+   * escape sequence is seen.
+   */
+  public static class InvalidEscapeSequenceException extends IOException {
+    private static final long serialVersionUID = -8164033650142593305L;
+
+    InvalidEscapeSequenceException(final String description) {
+      super(description);
+    }
+  }
+
+  public static ByteString unescapeBytes(CharSequence charString)
+          throws TextFormatEscaper.InvalidEscapeSequenceException {
+    // First convert the Java character sequence to UTF-8 bytes.
+    ByteString input = ByteString.copyFromUtf8(charString.toString());
+    // Then unescape certain byte sequences introduced by ASCII '\\'.  The valid
+    // escapes can all be expressed with ASCII characters, so it is safe to
+    // operate on bytes here.
+    //
+    // Unescaping the input byte array will result in a byte sequence that's no
+    // longer than the input.  That's because each escape sequence is between
+    // two and four bytes long and stands for a single byte.
+    final byte[] result = new byte[input.size()];
+    int pos = 0;
+    for (int i = 0; i < input.size(); i++) {
+      byte c = input.byteAt(i);
+      if (c == '\\') {
+        if (i + 1 < input.size()) {
+          ++i;
+          c = input.byteAt(i);
+          if (isOctal(c)) {
+            // Octal escape.
+            int code = digitValue(c);
+            if (i + 1 < input.size() && isOctal(input.byteAt(i + 1))) {
+              ++i;
+              code = code * 8 + digitValue(input.byteAt(i));
+            }
+            if (i + 1 < input.size() && isOctal(input.byteAt(i + 1))) {
+              ++i;
+              code = code * 8 + digitValue(input.byteAt(i));
+            }
+            // TODO: Check that 0 <= code && code <= 0xFF.
+            result[pos++] = (byte) code;
+          } else {
+            switch (c) {
+              case 'a':
+                result[pos++] = 0x07;
+                break;
+              case 'b':
+                result[pos++] = '\b';
+                break;
+              case 'f':
+                result[pos++] = '\f';
+                break;
+              case 'n':
+                result[pos++] = '\n';
+                break;
+              case 'r':
+                result[pos++] = '\r';
+                break;
+              case 't':
+                result[pos++] = '\t';
+                break;
+              case 'v':
+                result[pos++] = 0x0b;
+                break;
+              case '\\':
+                result[pos++] = '\\';
+                break;
+              case '\'':
+                result[pos++] = '\'';
+                break;
+              case '"':
+                result[pos++] = '\"';
+                break;
+              case '?':
+                result[pos++] = '?';
+                break;
+
+              case 'x':
+                // hex escape
+                int code = 0;
+                if (i + 1 < input.size() && isHex(input.byteAt(i + 1))) {
+                  ++i;
+                  code = digitValue(input.byteAt(i));
+                } else {
+                  throw new TextFormatEscaper.InvalidEscapeSequenceException(
+                          "Invalid escape sequence: '\\x' with no digits");
+                }
+                if (i + 1 < input.size() && isHex(input.byteAt(i + 1))) {
+                  ++i;
+                  code = code * 16 + digitValue(input.byteAt(i));
+                }
+                result[pos++] = (byte) code;
+                break;
+
+              case 'u':
+                // Unicode escape
+                ++i;
+                if (i + 3 < input.size()
+                        && isHex(input.byteAt(i))
+                        && isHex(input.byteAt(i + 1))
+                        && isHex(input.byteAt(i + 2))
+                        && isHex(input.byteAt(i + 3))) {
+                  char ch =
+                          (char)
+                                  (digitValue(input.byteAt(i)) << 12
+                                          | digitValue(input.byteAt(i + 1)) << 8
+                                          | digitValue(input.byteAt(i + 2)) << 4
+                                          | digitValue(input.byteAt(i + 3)));
+
+                  if (ch >= Character.MIN_SURROGATE && ch <= Character.MAX_SURROGATE) {
+                    throw new TextFormatEscaper.InvalidEscapeSequenceException(
+                            "Invalid escape sequence: '\\u' refers to a surrogate");
+                  }
+                  byte[] chUtf8 = Character.toString(ch).getBytes(Internal.UTF_8);
+                  System.arraycopy(chUtf8, 0, result, pos, chUtf8.length);
+                  pos += chUtf8.length;
+                  i += 3;
+                } else {
+                  throw new TextFormatEscaper.InvalidEscapeSequenceException(
+                          "Invalid escape sequence: '\\u' with too few hex chars");
+                }
+                break;
+
+              case 'U':
+                // Unicode escape
+                ++i;
+                if (i + 7 >= input.size()) {
+                  throw new TextFormatEscaper.InvalidEscapeSequenceException(
+                          "Invalid escape sequence: '\\U' with too few hex chars");
+                }
+                int codepoint = 0;
+                for (int offset = i; offset < i + 8; offset++) {
+                  byte b = input.byteAt(offset);
+                  if (!isHex(b)) {
+                    throw new TextFormatEscaper.InvalidEscapeSequenceException(
+                            "Invalid escape sequence: '\\U' with too few hex chars");
+                  }
+                  codepoint = (codepoint << 4) | digitValue(b);
+                }
+                if (!Character.isValidCodePoint(codepoint)) {
+                  throw new TextFormatEscaper.InvalidEscapeSequenceException(
+                          "Invalid escape sequence: '\\U"
+                                  + input.substring(i, i + 8).toStringUtf8()
+                                  + "' is not a valid code point value");
+                }
+                Character.UnicodeBlock unicodeBlock = Character.UnicodeBlock.of(codepoint);
+                if (unicodeBlock != null
+                        && (unicodeBlock.equals(Character.UnicodeBlock.LOW_SURROGATES)
+                        || unicodeBlock.equals(Character.UnicodeBlock.HIGH_SURROGATES)
+                        || unicodeBlock.equals(
+                        Character.UnicodeBlock.HIGH_PRIVATE_USE_SURROGATES))) {
+                  throw new TextFormatEscaper.InvalidEscapeSequenceException(
+                          "Invalid escape sequence: '\\U"
+                                  + input.substring(i, i + 8).toStringUtf8()
+                                  + "' refers to a surrogate code unit");
+                }
+                int[] codepoints = new int[1];
+                codepoints[0] = codepoint;
+                byte[] chUtf8 = new String(codepoints, 0, 1).getBytes(Internal.UTF_8);
+                System.arraycopy(chUtf8, 0, result, pos, chUtf8.length);
+                pos += chUtf8.length;
+                i += 7;
+                break;
+
+              default:
+                throw new TextFormatEscaper.InvalidEscapeSequenceException(
+                        "Invalid escape sequence: '\\" + (char) c + '\'');
+            }
+          }
+        } else {
+          throw new TextFormatEscaper.InvalidEscapeSequenceException(
+                  "Invalid escape sequence: '\\' at end of string.");
+        }
+      } else {
+        result[pos++] = c;
+      }
+    }
+
+    return result.length == pos
+            ? ByteString.wrap(result) // This reference has not been out of our control.
+            : ByteString.copyFrom(result, 0, pos);
+  }
 }
diff --git a/protobuf-api/src/main/java/com/google/protobuf/TextFormatInternal.java b/protobuf-api/src/main/java/com/google/protobuf/TextFormatInternal.java
new file mode 100644
index 0000000..e5b08de
--- /dev/null
+++ b/protobuf-api/src/main/java/com/google/protobuf/TextFormatInternal.java
@@ -0,0 +1,732 @@
+package com.google.protobuf;
+
+import java.io.IOException;
+import java.math.BigInteger;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+
+public class TextFormatInternal {
+    /**
+     * Parse a 32-bit signed integer from the text. Unlike the Java standard {@code
+     * Integer.parseInt()}, this function recognizes the prefixes "0x" and "0" to signify hexadecimal
+     * and octal numbers, respectively.
+     */
+    static int parseInt32(final String text) throws NumberFormatException {
+        return (int) parseInteger(text, true, false);
+    }
+
+    /**
+     * Parse a 32-bit unsigned integer from the text. Unlike the Java standard {@code
+     * Integer.parseInt()}, this function recognizes the prefixes "0x" and "0" to signify hexadecimal
+     * and octal numbers, respectively. The result is coerced to a (signed) {@code int} when returned
+     * since Java has no unsigned integer type.
+     */
+    static int parseUInt32(final String text) throws NumberFormatException {
+        return (int) parseInteger(text, false, false);
+    }
+
+    /**
+     * Parse a 64-bit signed integer from the text. Unlike the Java standard {@code
+     * Integer.parseInt()}, this function recognizes the prefixes "0x" and "0" to signify hexadecimal
+     * and octal numbers, respectively.
+     */
+    static long parseInt64(final String text) throws NumberFormatException {
+        return parseInteger(text, true, true);
+    }
+
+    /**
+     * Parse a 64-bit unsigned integer from the text. Unlike the Java standard {@code
+     * Integer.parseInt()}, this function recognizes the prefixes "0x" and "0" to signify hexadecimal
+     * and octal numbers, respectively. The result is coerced to a (signed) {@code long} when returned
+     * since Java has no unsigned long type.
+     */
+    static long parseUInt64(final String text) throws NumberFormatException {
+        return parseInteger(text, false, true);
+    }
+
+    private static long parseInteger(final String text, final boolean isSigned, final boolean isLong)
+            throws NumberFormatException {
+        int pos = 0;
+
+        boolean negative = false;
+        if (text.startsWith("-", pos)) {
+            if (!isSigned) {
+                throw new NumberFormatException("Number must be positive: " + text);
+            }
+            ++pos;
+            negative = true;
+        }
+
+        int radix = 10;
+        if (text.startsWith("0x", pos)) {
+            pos += 2;
+            radix = 16;
+        } else if (text.startsWith("0", pos)) {
+            radix = 8;
+        }
+
+        final String numberText = text.substring(pos);
+
+        long result = 0;
+        if (numberText.length() < 16) {
+            // Can safely assume no overflow.
+            result = Long.parseLong(numberText, radix);
+            if (negative) {
+                result = -result;
+            }
+
+            // Check bounds.
+            // No need to check for 64-bit numbers since they'd have to be 16 chars
+            // or longer to overflow.
+            if (!isLong) {
+                if (isSigned) {
+                    if (result > Integer.MAX_VALUE || result < Integer.MIN_VALUE) {
+                        throw new NumberFormatException(
+                                "Number out of range for 32-bit signed integer: " + text);
+                    }
+                } else {
+                    if (result >= (1L << 32) || result < 0) {
+                        throw new NumberFormatException(
+                                "Number out of range for 32-bit unsigned integer: " + text);
+                    }
+                }
+            }
+        } else {
+            BigInteger bigValue = new BigInteger(numberText, radix);
+            if (negative) {
+                bigValue = bigValue.negate();
+            }
+
+            // Check bounds.
+            if (!isLong) {
+                if (isSigned) {
+                    if (bigValue.bitLength() > 31) {
+                        throw new NumberFormatException(
+                                "Number out of range for 32-bit signed integer: " + text);
+                    }
+                } else {
+                    if (bigValue.bitLength() > 32) {
+                        throw new NumberFormatException(
+                                "Number out of range for 32-bit unsigned integer: " + text);
+                    }
+                }
+            } else {
+                if (isSigned) {
+                    if (bigValue.bitLength() > 63) {
+                        throw new NumberFormatException(
+                                "Number out of range for 64-bit signed integer: " + text);
+                    }
+                } else {
+                    if (bigValue.bitLength() > 64) {
+                        throw new NumberFormatException(
+                                "Number out of range for 64-bit unsigned integer: " + text);
+                    }
+                }
+            }
+
+            result = bigValue.longValue();
+        }
+
+        return result;
+    }
+
+    /** Printer instance which escapes non-ASCII characters. */
+    public static TextFormatInternal.Printer printer() {
+        return TextFormatInternal.Printer.DEFAULT;
+    }
+
+    /** Helper class for converting protobufs to text. */
+    public static final class Printer {
+
+        // Printer instance which escapes non-ASCII characters.
+        private static final TextFormatInternal.Printer DEFAULT = new TextFormatInternal.Printer(true, TypeRegistry.getEmptyTypeRegistry());
+
+        /** Whether to escape non ASCII characters with backslash and octal. */
+        private final boolean escapeNonAscii;
+
+        private final TypeRegistry typeRegistry;
+
+        private Printer(boolean escapeNonAscii, TypeRegistry typeRegistry) {
+            this.escapeNonAscii = escapeNonAscii;
+            this.typeRegistry = typeRegistry;
+        }
+
+        /**
+         * Return a new Printer instance with the specified escape mode.
+         *
+         * @param escapeNonAscii If true, the new Printer will escape non-ASCII characters (this is the
+         *     default behavior. If false, the new Printer will print non-ASCII characters as is. In
+         *     either case, the new Printer still escapes newlines and quotes in strings.
+         * @return a new Printer that clones all other configurations from the current {@link TextFormatInternal.Printer},
+         *     with the escape mode set to the given parameter.
+         */
+        public TextFormatInternal.Printer escapingNonAscii(boolean escapeNonAscii) {
+            return new TextFormatInternal.Printer(escapeNonAscii, typeRegistry);
+        }
+
+        /**
+         * Creates a new {@link TextFormatInternal.Printer} using the given typeRegistry. The new Printer clones all other
+         * configurations from the current {@link TextFormatInternal.Printer}.
+         *
+         * @throws IllegalArgumentException if a registry is already set.
+         */
+        public TextFormatInternal.Printer usingTypeRegistry(TypeRegistry typeRegistry) {
+            if (this.typeRegistry != TypeRegistry.getEmptyTypeRegistry()) {
+                throw new IllegalArgumentException("Only one typeRegistry is allowed.");
+            }
+            return new TextFormatInternal.Printer(escapeNonAscii, typeRegistry);
+        }
+
+        /**
+         * Outputs a textual representation of the Protocol Message supplied into the parameter output.
+         * (This representation is the new version of the classic "ProtocolPrinter" output from the
+         * original Protocol Buffer system)
+         */
+        public void print(final MessageOrBuilder message, final Appendable output) throws IOException {
+            print(message, multiLineOutput(output));
+        }
+
+        /** Outputs a textual representation of {@code fields} to {@code output}. */
+        public void print(final UnknownFieldSet fields, final Appendable output) throws IOException {
+            printUnknownFields(fields, multiLineOutput(output));
+        }
+
+        private void print(final MessageOrBuilder message, final TextFormatInternal.TextGenerator generator)
+                throws IOException {
+            if (message.getDescriptorForType().getFullName().equals("google.protobuf.Any")
+                    && printAny(message, generator)) {
+                return;
+            }
+            printMessage(message, generator);
+        }
+
+        /**
+         * Attempt to print the 'google.protobuf.Any' message in a human-friendly format. Returns false
+         * if the message isn't a valid 'google.protobuf.Any' message (in which case the message should
+         * be rendered just like a regular message to help debugging).
+         */
+        private boolean printAny(final MessageOrBuilder message, final TextFormatInternal.TextGenerator generator)
+                throws IOException {
+            Descriptors.Descriptor messageType = message.getDescriptorForType();
+            Descriptors.FieldDescriptor typeUrlField = messageType.findFieldByNumber(1);
+            Descriptors.FieldDescriptor valueField = messageType.findFieldByNumber(2);
+            if (typeUrlField == null
+                    || typeUrlField.getType() != Descriptors.FieldDescriptor.Type.STRING
+                    || valueField == null
+                    || valueField.getType() != Descriptors.FieldDescriptor.Type.BYTES) {
+                // The message may look like an Any but isn't actually an Any message (might happen if the
+                // user tries to use DynamicMessage to construct an Any from incomplete Descriptor).
+                return false;
+            }
+            String typeUrl = (String) message.getField(typeUrlField);
+            // If type_url is not set, we will not be able to decode the content of the value, so just
+            // print out the Any like a regular message.
+            if (typeUrl.isEmpty()) {
+                return false;
+            }
+            Object value = message.getField(valueField);
+
+            Message.Builder contentBuilder = null;
+            try {
+                Descriptors.Descriptor contentType = typeRegistry.getDescriptorForTypeUrl(typeUrl);
+                if (contentType == null) {
+                    return false;
+                }
+                contentBuilder = DynamicMessage.getDefaultInstance(contentType).newBuilderForType();
+                contentBuilder.mergeFrom((ByteString) value);
+            } catch (InvalidProtocolBufferException e) {
+                // The value of Any is malformed. We cannot print it out nicely, so fallback to printing out
+                // the type_url and value as bytes. Note that we fail open here to be consistent with
+                // text_format.cc, and also to allow a way for users to inspect the content of the broken
+                // message.
+                return false;
+            }
+            generator.print("[");
+            generator.print(typeUrl);
+            generator.print("] {");
+            generator.eol();
+            generator.indent();
+            print(contentBuilder, generator);
+            generator.outdent();
+            generator.print("}");
+            generator.eol();
+            return true;
+        }
+
+        public String printFieldToString(final Descriptors.FieldDescriptor field, final Object value) {
+            try {
+                final StringBuilder text = new StringBuilder();
+                printField(field, value, text);
+                return text.toString();
+            } catch (IOException e) {
+                throw new IllegalStateException(e);
+            }
+        }
+
+        public void printField(final Descriptors.FieldDescriptor field, final Object value, final Appendable output)
+                throws IOException {
+            printField(field, value, multiLineOutput(output));
+        }
+
+        private void printField(
+                final Descriptors.FieldDescriptor field, final Object value, final TextFormatInternal.TextGenerator generator)
+                throws IOException {
+            // Sort map field entries by key
+            if (field.isMapField()) {
+                List<TextFormatInternal.Printer.MapEntryAdapter> adapters = new ArrayList<>();
+                for (Object entry : (List<?>) value) {
+                    adapters.add(new TextFormatInternal.Printer.MapEntryAdapter(entry, field));
+                }
+                Collections.sort(adapters);
+                for (TextFormatInternal.Printer.MapEntryAdapter adapter : adapters) {
+                    printSingleField(field, adapter.getEntry(), generator);
+                }
+            } else if (field.isRepeated()) {
+                // Repeated field.  Print each element.
+                for (Object element : (List<?>) value) {
+                    printSingleField(field, element, generator);
+                }
+            } else {
+                printSingleField(field, value, generator);
+            }
+        }
+
+        /** An adapter class that can take a {@link MapEntry} and returns its key and entry. */
+        private static class MapEntryAdapter implements Comparable<TextFormatInternal.Printer.MapEntryAdapter> {
+            private Object entry;
+
+            @SuppressWarnings({"rawtypes"})
+            private MapEntry mapEntry;
+
+            private final Descriptors.FieldDescriptor.JavaType fieldType;
+
+            MapEntryAdapter(Object entry, Descriptors.FieldDescriptor fieldDescriptor) {
+                if (entry instanceof MapEntry) {
+                    this.mapEntry = (MapEntry) entry;
+                } else {
+                    this.entry = entry;
+                }
+                this.fieldType = extractFieldType(fieldDescriptor);
+            }
+
+            private static Descriptors.FieldDescriptor.JavaType extractFieldType(Descriptors.FieldDescriptor fieldDescriptor) {
+                return fieldDescriptor.getMessageType().getFields().get(0).getJavaType();
+            }
+
+            Object getKey() {
+                if (mapEntry != null) {
+                    return mapEntry.getKey();
+                }
+                return null;
+            }
+
+            Object getEntry() {
+                if (mapEntry != null) {
+                    return mapEntry;
+                }
+                return entry;
+            }
+
+            @Override
+            public int compareTo(TextFormatInternal.Printer.MapEntryAdapter b) {
+                if (getKey() == null || b.getKey() == null) {
+//                    logger.info("Invalid key for map field.");
+                    return -1;
+                }
+                switch (fieldType) {
+                    case BOOLEAN:
+                        return Boolean.valueOf((boolean) getKey()).compareTo((boolean) b.getKey());
+                    case LONG:
+                        return Long.valueOf((long) getKey()).compareTo((long) b.getKey());
+                    case INT:
+                        return Integer.valueOf((int) getKey()).compareTo((int) b.getKey());
+                    case STRING:
+                        String aString = (String) getKey();
+                        String bString = (String) b.getKey();
+                        if (aString == null && bString == null) {
+                            return 0;
+                        } else if (aString == null && bString != null) {
+                            return -1;
+                        } else if (aString != null && bString == null) {
+                            return 1;
+                        } else {
+                            return aString.compareTo(bString);
+                        }
+                    default:
+                        return 0;
+                }
+            }
+        }
+
+        /**
+         * Outputs a textual representation of the value of given field value.
+         *
+         * @param field the descriptor of the field
+         * @param value the value of the field
+         * @param output the output to which to append the formatted value
+         * @throws ClassCastException if the value is not appropriate for the given field descriptor
+         * @throws IOException if there is an exception writing to the output
+         */
+        public void printFieldValue(
+                final Descriptors.FieldDescriptor field, final Object value, final Appendable output)
+                throws IOException {
+            printFieldValue(field, value, multiLineOutput(output));
+        }
+
+        private void printFieldValue(
+                final Descriptors.FieldDescriptor field, final Object value, final TextFormatInternal.TextGenerator generator)
+                throws IOException {
+            switch (field.getType()) {
+                case INT32:
+                case SINT32:
+                case SFIXED32:
+                    generator.print(((Integer) value).toString());
+                    break;
+
+                case INT64:
+                case SINT64:
+                case SFIXED64:
+                    generator.print(((Long) value).toString());
+                    break;
+
+                case BOOL:
+                    generator.print(((Boolean) value).toString());
+                    break;
+
+                case FLOAT:
+                    generator.print(((Float) value).toString());
+                    break;
+
+                case DOUBLE:
+                    generator.print(((Double) value).toString());
+                    break;
+
+                case UINT32:
+                case FIXED32:
+                    generator.print(unsignedToString((Integer) value));
+                    break;
+
+                case UINT64:
+                case FIXED64:
+                    generator.print(unsignedToString((Long) value));
+                    break;
+
+                case STRING:
+                    generator.print("\"");
+                    generator.print(
+                            escapeNonAscii
+                                    ? TextFormatEscaper.escapeText((String) value)
+                                    : escapeDoubleQuotesAndBackslashes((String) value).replace("\n", "\\n"));
+                    generator.print("\"");
+                    break;
+
+                case BYTES:
+                    generator.print("\"");
+                    if (value instanceof ByteString) {
+                        generator.print(escapeBytes((ByteString) value));
+                    } else {
+                        generator.print(escapeBytes((byte[]) value));
+                    }
+                    generator.print("\"");
+                    break;
+
+                case ENUM:
+                    generator.print(((Descriptors.EnumValueDescriptor) value).getName());
+                    break;
+
+                case MESSAGE:
+                case GROUP:
+                    print((MessageOrBuilder) value, generator);
+                    break;
+            }
+        }
+
+        /** Like {@code print()}, but writes directly to a {@code String} and returns it. */
+        public String printToString(final MessageOrBuilder message) {
+            try {
+                final StringBuilder text = new StringBuilder();
+                print(message, text);
+                return text.toString();
+            } catch (IOException e) {
+                throw new IllegalStateException(e);
+            }
+        }
+        /** Like {@code print()}, but writes directly to a {@code String} and returns it. */
+        public String printToString(final UnknownFieldSet fields) {
+            try {
+                final StringBuilder text = new StringBuilder();
+                print(fields, text);
+                return text.toString();
+            } catch (IOException e) {
+                throw new IllegalStateException(e);
+            }
+        }
+
+        /**
+         * Generates a human readable form of this message, useful for debugging and other purposes,
+         * with no newline characters.
+         */
+        public String shortDebugString(final MessageOrBuilder message) {
+            try {
+                final StringBuilder text = new StringBuilder();
+                print(message, singleLineOutput(text));
+                return text.toString();
+            } catch (IOException e) {
+                throw new IllegalStateException(e);
+            }
+        }
+
+        /**
+         * Generates a human readable form of the field, useful for debugging and other purposes, with
+         * no newline characters.
+         */
+        public String shortDebugString(final Descriptors.FieldDescriptor field, final Object value) {
+            try {
+                final StringBuilder text = new StringBuilder();
+                printField(field, value, singleLineOutput(text));
+                return text.toString();
+            } catch (IOException e) {
+                throw new IllegalStateException(e);
+            }
+        }
+
+        /**
+         * Generates a human readable form of the unknown fields, useful for debugging and other
+         * purposes, with no newline characters.
+         */
+        public String shortDebugString(final UnknownFieldSet fields) {
+            try {
+                final StringBuilder text = new StringBuilder();
+                printUnknownFields(fields, singleLineOutput(text));
+                return text.toString();
+            } catch (IOException e) {
+                throw new IllegalStateException(e);
+            }
+        }
+
+        private static void printUnknownFieldValue(
+                final int tag, final Object value, final TextFormatInternal.TextGenerator generator) throws IOException {
+            switch (WireFormat.getTagWireType(tag)) {
+                case WireFormat.WIRETYPE_VARINT:
+                    generator.print(unsignedToString((Long) value));
+                    break;
+                case WireFormat.WIRETYPE_FIXED32:
+                    generator.print(String.format((Locale) null, "0x%08x", (Integer) value));
+                    break;
+                case WireFormat.WIRETYPE_FIXED64:
+                    generator.print(String.format((Locale) null, "0x%016x", (Long) value));
+                    break;
+                case WireFormat.WIRETYPE_LENGTH_DELIMITED:
+                    try {
+                        // Try to parse and print the field as an embedded message
+                        UnknownFieldSet message = UnknownFieldSet.parseFrom((ByteString) value);
+                        generator.print("{");
+                        generator.eol();
+                        generator.indent();
+                        printUnknownFields(message, generator);
+                        generator.outdent();
+                        generator.print("}");
+                    } catch (InvalidProtocolBufferException e) {
+                        // If not parseable as a message, print as a String
+                        generator.print("\"");
+                        generator.print(escapeBytes((ByteString) value));
+                        generator.print("\"");
+                    }
+                    break;
+                case WireFormat.WIRETYPE_START_GROUP:
+                    printUnknownFields((UnknownFieldSet) value, generator);
+                    break;
+                default:
+                    throw new IllegalArgumentException("Bad tag: " + tag);
+            }
+        }
+
+        private void printMessage(final MessageOrBuilder message, final TextFormatInternal.TextGenerator generator)
+                throws IOException {
+            for (Map.Entry<Descriptors.FieldDescriptor, Object> field : message.getAllFields().entrySet()) {
+                printField(field.getKey(), field.getValue(), generator);
+            }
+            printUnknownFields(message.getUnknownFields(), generator);
+        }
+
+        private void printSingleField(
+                final Descriptors.FieldDescriptor field, final Object value, final TextFormatInternal.TextGenerator generator)
+                throws IOException {
+            if (field.isExtension()) {
+                generator.print("[");
+                // We special-case MessageSet elements for compatibility with proto1.
+                if (field.getContainingType().getOptions().getMessageSetWireFormat()
+                        && (field.getType() == Descriptors.FieldDescriptor.Type.MESSAGE)
+                        && (field.isOptional())
+                        // object equality
+                        && (field.getExtensionScope() == field.getMessageType())) {
+                    generator.print(field.getMessageType().getFullName());
+                } else {
+                    generator.print(field.getFullName());
+                }
+                generator.print("]");
+            } else {
+                if (field.getType() == Descriptors.FieldDescriptor.Type.GROUP) {
+                    // Groups must be serialized with their original capitalization.
+                    generator.print(field.getMessageType().getName());
+                } else {
+                    generator.print(field.getName());
+                }
+            }
+
+            if (field.getJavaType() == Descriptors.FieldDescriptor.JavaType.MESSAGE) {
+                generator.print(" {");
+                generator.eol();
+                generator.indent();
+            } else {
+                generator.print(": ");
+            }
+
+            printFieldValue(field, value, generator);
+
+            if (field.getJavaType() == Descriptors.FieldDescriptor.JavaType.MESSAGE) {
+                generator.outdent();
+                generator.print("}");
+            }
+            generator.eol();
+        }
+
+        private static void printUnknownFields(
+                final UnknownFieldSet unknownFields, final TextFormatInternal.TextGenerator generator) throws IOException {
+            for (Map.Entry<Integer, UnknownFieldSet.Field> entry : unknownFields.asMap().entrySet()) {
+                final int number = entry.getKey();
+                final UnknownFieldSet.Field field = entry.getValue();
+                printUnknownField(number, WireFormat.WIRETYPE_VARINT, field.getVarintList(), generator);
+                printUnknownField(number, WireFormat.WIRETYPE_FIXED32, field.getFixed32List(), generator);
+                printUnknownField(number, WireFormat.WIRETYPE_FIXED64, field.getFixed64List(), generator);
+                printUnknownField(
+                        number,
+                        WireFormat.WIRETYPE_LENGTH_DELIMITED,
+                        field.getLengthDelimitedList(),
+                        generator);
+                for (final UnknownFieldSet value : field.getGroupList()) {
+                    generator.print(entry.getKey().toString());
+                    generator.print(" {");
+                    generator.eol();
+                    generator.indent();
+                    printUnknownFields(value, generator);
+                    generator.outdent();
+                    generator.print("}");
+                    generator.eol();
+                }
+            }
+        }
+
+        private static void printUnknownField(
+                final int number, final int wireType, final List<?> values, final TextFormatInternal.TextGenerator generator)
+                throws IOException {
+            for (final Object value : values) {
+                generator.print(String.valueOf(number));
+                generator.print(": ");
+                printUnknownFieldValue(wireType, value, generator);
+                generator.eol();
+            }
+        }
+    }
+
+    /** Convert an unsigned 32-bit integer to a string. */
+    public static String unsignedToString(final int value) {
+        if (value >= 0) {
+            return Integer.toString(value);
+        } else {
+            return Long.toString(value & 0x00000000FFFFFFFFL);
+        }
+    }
+
+    /** Convert an unsigned 64-bit integer to a string. */
+    public static String unsignedToString(final long value) {
+        if (value >= 0) {
+            return Long.toString(value);
+        } else {
+            // Pull off the most-significant bit so that BigInteger doesn't think
+            // the number is negative, then set it again using setBit().
+            return BigInteger.valueOf(value & 0x7FFFFFFFFFFFFFFFL).setBit(63).toString();
+        }
+    }
+
+    private static TextFormatInternal.TextGenerator multiLineOutput(Appendable output) {
+        return new TextFormatInternal.TextGenerator(output, false);
+    }
+
+    private static TextFormatInternal.TextGenerator singleLineOutput(Appendable output) {
+        return new TextFormatInternal.TextGenerator(output, true);
+    }
+
+    private static String escapeBytes(ByteString input) {
+        return TextFormatEscaper.escapeBytes(input);
+    }
+
+    public static String escapeBytes(byte[] input) {
+        return TextFormatEscaper.escapeBytes(input);
+    }
+
+    public static String escapeDoubleQuotesAndBackslashes(final String input) {
+        return TextFormatEscaper.escapeDoubleQuotesAndBackslashes(input);
+    }
+
+    /** An inner class for writing text to the output stream. */
+    private static final class TextGenerator {
+        private final Appendable output;
+        private final StringBuilder indent = new StringBuilder();
+        private final boolean singleLineMode;
+        // While technically we are "at the start of a line" at the very beginning of the output, all
+        // we would do in response to this is emit the (zero length) indentation, so it has no effect.
+        // Setting it false here does however suppress an unwanted leading space in single-line mode.
+        private boolean atStartOfLine = false;
+
+        private TextGenerator(final Appendable output, boolean singleLineMode) {
+            this.output = output;
+            this.singleLineMode = singleLineMode;
+        }
+
+        /**
+         * Indent text by two spaces. After calling Indent(), two spaces will be inserted at the
+         * beginning of each line of text. Indent() may be called multiple times to produce deeper
+         * indents.
+         */
+        public void indent() {
+            indent.append("  ");
+        }
+
+        /** Reduces the current indent level by two spaces, or crashes if the indent level is zero. */
+        public void outdent() {
+            final int length = indent.length();
+            if (length == 0) {
+                throw new IllegalArgumentException(" Outdent() without matching Indent().");
+            }
+            indent.setLength(length - 2);
+        }
+
+        /**
+         * Print text to the output stream. Bare newlines are never expected to be passed to this
+         * method; to indicate the end of a line, call "eol()".
+         */
+        public void print(final CharSequence text) throws IOException {
+            if (atStartOfLine) {
+                atStartOfLine = false;
+                output.append(singleLineMode ? " " : indent);
+            }
+            output.append(text);
+        }
+
+        /**
+         * Signifies reaching the "end of the current line" in the output. In single-line mode, this
+         * does not result in a newline being emitted, but ensures that a separating space is written
+         * before the next output.
+         */
+        public void eol() throws IOException {
+            if (!singleLineMode) {
+                output.append("\n");
+            }
+            atStartOfLine = true;
+        }
+    }
+}
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/Timestamp.java b/protobuf-api/src/main/java/com/google/protobuf/Timestamp.java
similarity index 96%
rename from protobuf-sdk/src/main/java/com/google/protobuf/Timestamp.java
rename to protobuf-api/src/main/java/com/google/protobuf/Timestamp.java
index a196076..a494a67 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/Timestamp.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/Timestamp.java
@@ -100,12 +100,12 @@
  * Protobuf type {@code google.protobuf.Timestamp}
  */
 public final class Timestamp extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.Timestamp)
     TimestampOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use Timestamp.newBuilder() to construct.
-  private Timestamp(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private Timestamp(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private Timestamp() {
@@ -124,7 +124,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.TimestampProto.internal_static_google_protobuf_Timestamp_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -277,20 +277,20 @@ public static com.google.protobuf.Timestamp parseFrom(
   }
   public static com.google.protobuf.Timestamp parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Timestamp parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.Timestamp parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -298,20 +298,20 @@ public static com.google.protobuf.Timestamp parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.Timestamp parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Timestamp parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -331,7 +331,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -431,7 +431,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.Timestamp}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.Timestamp)
       com.google.protobuf.TimestampOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -440,7 +440,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.TimestampProto.internal_static_google_protobuf_Timestamp_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -453,7 +453,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/TimestampOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/TimestampOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/TimestampOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/TimestampOrBuilder.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/TimestampProto.java b/protobuf-api/src/main/java/com/google/protobuf/TimestampProto.java
similarity index 93%
rename from protobuf-sdk/src/main/java/com/google/protobuf/TimestampProto.java
rename to protobuf-api/src/main/java/com/google/protobuf/TimestampProto.java
index 8cf5af4..2512638 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/TimestampProto.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/TimestampProto.java
@@ -18,7 +18,7 @@ public static void registerAllExtensions(
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_Timestamp_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_Timestamp_fieldAccessorTable;
 
   public static com.google.protobuf.Descriptors.FileDescriptor
@@ -43,7 +43,7 @@ public static void registerAllExtensions(
     internal_static_google_protobuf_Timestamp_descriptor =
       getDescriptor().getMessageTypes().get(0);
     internal_static_google_protobuf_Timestamp_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_Timestamp_descriptor,
         new java.lang.String[] { "Seconds", "Nanos", });
   }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/Type.java b/protobuf-api/src/main/java/com/google/protobuf/Type.java
similarity index 94%
rename from protobuf-sdk/src/main/java/com/google/protobuf/Type.java
rename to protobuf-api/src/main/java/com/google/protobuf/Type.java
index 88b3492..1b70195 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/Type.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/Type.java
@@ -12,12 +12,12 @@
  * Protobuf type {@code google.protobuf.Type}
  */
 public final class Type extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.Type)
     TypeOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use Type.newBuilder() to construct.
-  private Type(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private Type(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private Type() {
@@ -43,7 +43,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.TypeProto.internal_static_google_protobuf_Type_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -398,14 +398,14 @@ public final boolean isInitialized() {
   @java.lang.Override
   public void writeTo(com.google.protobuf.CodedOutputStream output)
                       throws java.io.IOException {
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 1, name_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(name_)) {
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 1, name_);
     }
     for (int i = 0; i < fields_.size(); i++) {
       output.writeMessage(2, fields_.get(i));
     }
     for (int i = 0; i < oneofs_.size(); i++) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 3, oneofs_.getRaw(i));
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 3, oneofs_.getRaw(i));
     }
     for (int i = 0; i < options_.size(); i++) {
       output.writeMessage(4, options_.get(i));
@@ -416,8 +416,8 @@ public void writeTo(com.google.protobuf.CodedOutputStream output)
     if (syntax_ != com.google.protobuf.Syntax.SYNTAX_PROTO2.getNumber()) {
       output.writeEnum(6, syntax_);
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(edition_)) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 7, edition_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(edition_)) {
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 7, edition_);
     }
     getUnknownFields().writeTo(output);
   }
@@ -428,8 +428,8 @@ public int getSerializedSize() {
     if (size != -1) return size;
 
     size = 0;
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, name_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(name_)) {
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(1, name_);
     }
     for (int i = 0; i < fields_.size(); i++) {
       size += com.google.protobuf.CodedOutputStream
@@ -455,8 +455,8 @@ public int getSerializedSize() {
       size += com.google.protobuf.CodedOutputStream
         .computeEnumSize(6, syntax_);
     }
-    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(edition_)) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(7, edition_);
+    if (!com.google.protobuf.GeneratedMessageV3Internal.isStringEmpty(edition_)) {
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(7, edition_);
     }
     size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
@@ -561,20 +561,20 @@ public static com.google.protobuf.Type parseFrom(
   }
   public static com.google.protobuf.Type parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Type parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.Type parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -582,20 +582,20 @@ public static com.google.protobuf.Type parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.Type parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Type parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -615,7 +615,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -627,7 +627,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.Type}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.Type)
       com.google.protobuf.TypeOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -636,7 +636,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.TypeProto.internal_static_google_protobuf_Type_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -649,12 +649,12 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
       maybeForceBuilderInitialization();
     }
     private void maybeForceBuilderInitialization() {
-      if (com.google.protobuf.GeneratedMessageV3
+      if (com.google.protobuf.GeneratedMessageV3Internal
               .alwaysUseFieldBuilders) {
         getFieldsFieldBuilder();
         getOptionsFieldBuilder();
@@ -835,7 +835,7 @@ public Builder mergeFrom(com.google.protobuf.Type other) {
             fields_ = other.fields_;
             bitField0_ = (bitField0_ & ~0x00000002);
             fieldsBuilder_ = 
-              com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+              com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                  getFieldsFieldBuilder() : null;
           } else {
             fieldsBuilder_.addAllMessages(other.fields_);
@@ -871,7 +871,7 @@ public Builder mergeFrom(com.google.protobuf.Type other) {
             options_ = other.options_;
             bitField0_ = (bitField0_ & ~0x00000008);
             optionsBuilder_ = 
-              com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+              com.google.protobuf.GeneratedMessageV3Internal.alwaysUseFieldBuilders ?
                  getOptionsFieldBuilder() : null;
           } else {
             optionsBuilder_.addAllMessages(other.options_);
@@ -1087,8 +1087,8 @@ private void ensureFieldsIsMutable() {
        }
     }
 
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Field, com.google.protobuf.Field.Builder, com.google.protobuf.FieldOrBuilder> fieldsBuilder_;
+    private RepeatedFieldBuilderV3Internal<
+            Field, Field.Builder, FieldOrBuilder> fieldsBuilder_;
 
     /**
      * <pre>
@@ -1375,12 +1375,12 @@ public com.google.protobuf.Field.Builder addFieldsBuilder(
          getFieldsBuilderList() {
       return getFieldsFieldBuilder().getBuilderList();
     }
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Field, com.google.protobuf.Field.Builder, com.google.protobuf.FieldOrBuilder> 
+    private RepeatedFieldBuilderV3Internal<
+            Field, Field.Builder, FieldOrBuilder>
         getFieldsFieldBuilder() {
       if (fieldsBuilder_ == null) {
-        fieldsBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-            com.google.protobuf.Field, com.google.protobuf.Field.Builder, com.google.protobuf.FieldOrBuilder>(
+        fieldsBuilder_ = new RepeatedFieldBuilderV3Internal<
+                    Field, Field.Builder, FieldOrBuilder>(
                 fields_,
                 ((bitField0_ & 0x00000002) != 0),
                 getParentForChildren(),
@@ -1546,8 +1546,8 @@ private void ensureOptionsIsMutable() {
        }
     }
 
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Option, com.google.protobuf.Option.Builder, com.google.protobuf.OptionOrBuilder> optionsBuilder_;
+    private RepeatedFieldBuilderV3Internal<
+            Option, Option.Builder, OptionOrBuilder> optionsBuilder_;
 
     /**
      * <pre>
@@ -1834,12 +1834,12 @@ public com.google.protobuf.Option.Builder addOptionsBuilder(
          getOptionsBuilderList() {
       return getOptionsFieldBuilder().getBuilderList();
     }
-    private com.google.protobuf.RepeatedFieldBuilderV3<
-        com.google.protobuf.Option, com.google.protobuf.Option.Builder, com.google.protobuf.OptionOrBuilder> 
+    private RepeatedFieldBuilderV3Internal<
+            Option, Option.Builder, OptionOrBuilder>
         getOptionsFieldBuilder() {
       if (optionsBuilder_ == null) {
-        optionsBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
-            com.google.protobuf.Option, com.google.protobuf.Option.Builder, com.google.protobuf.OptionOrBuilder>(
+        optionsBuilder_ = new RepeatedFieldBuilderV3Internal<
+                    Option, Option.Builder, OptionOrBuilder>(
                 options_,
                 ((bitField0_ & 0x00000008) != 0),
                 getParentForChildren(),
@@ -1850,8 +1850,8 @@ public com.google.protobuf.Option.Builder addOptionsBuilder(
     }
 
     private com.google.protobuf.SourceContext sourceContext_;
-    private com.google.protobuf.SingleFieldBuilderV3<
-        com.google.protobuf.SourceContext, com.google.protobuf.SourceContext.Builder, com.google.protobuf.SourceContextOrBuilder> sourceContextBuilder_;
+    private SingleFieldBuilderV3Internal<
+            SourceContext, SourceContext.Builder, SourceContextOrBuilder> sourceContextBuilder_;
     /**
      * <pre>
      * The source context.
@@ -1992,12 +1992,12 @@ public com.google.protobuf.SourceContextOrBuilder getSourceContextOrBuilder() {
      *
      * <code>.google.protobuf.SourceContext source_context = 5;</code>
      */
-    private com.google.protobuf.SingleFieldBuilderV3<
-        com.google.protobuf.SourceContext, com.google.protobuf.SourceContext.Builder, com.google.protobuf.SourceContextOrBuilder> 
+    private SingleFieldBuilderV3Internal<
+            SourceContext, SourceContext.Builder, SourceContextOrBuilder>
         getSourceContextFieldBuilder() {
       if (sourceContextBuilder_ == null) {
-        sourceContextBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-            com.google.protobuf.SourceContext, com.google.protobuf.SourceContext.Builder, com.google.protobuf.SourceContextOrBuilder>(
+        sourceContextBuilder_ = new SingleFieldBuilderV3Internal<
+                    SourceContext, SourceContext.Builder, SourceContextOrBuilder>(
                 getSourceContext(),
                 getParentForChildren(),
                 isClean());
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/TypeOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/TypeOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/TypeOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/TypeOrBuilder.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/TypeProto.java b/protobuf-api/src/main/java/com/google/protobuf/TypeProto.java
similarity index 90%
rename from protobuf-sdk/src/main/java/com/google/protobuf/TypeProto.java
rename to protobuf-api/src/main/java/com/google/protobuf/TypeProto.java
index 1cc1248..03a0e71 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/TypeProto.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/TypeProto.java
@@ -18,27 +18,27 @@ public static void registerAllExtensions(
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_Type_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_Type_fieldAccessorTable;
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_Field_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_Field_fieldAccessorTable;
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_Enum_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_Enum_fieldAccessorTable;
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_EnumValue_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_EnumValue_fieldAccessorTable;
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_Option_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_Option_fieldAccessorTable;
 
   public static com.google.protobuf.Descriptors.FileDescriptor
@@ -101,31 +101,31 @@ public static void registerAllExtensions(
     internal_static_google_protobuf_Type_descriptor =
       getDescriptor().getMessageTypes().get(0);
     internal_static_google_protobuf_Type_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_Type_descriptor,
         new java.lang.String[] { "Name", "Fields", "Oneofs", "Options", "SourceContext", "Syntax", "Edition", });
     internal_static_google_protobuf_Field_descriptor =
       getDescriptor().getMessageTypes().get(1);
     internal_static_google_protobuf_Field_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_Field_descriptor,
         new java.lang.String[] { "Kind", "Cardinality", "Number", "Name", "TypeUrl", "OneofIndex", "Packed", "Options", "JsonName", "DefaultValue", });
     internal_static_google_protobuf_Enum_descriptor =
       getDescriptor().getMessageTypes().get(2);
     internal_static_google_protobuf_Enum_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_Enum_descriptor,
         new java.lang.String[] { "Name", "Enumvalue", "Options", "SourceContext", "Syntax", "Edition", });
     internal_static_google_protobuf_EnumValue_descriptor =
       getDescriptor().getMessageTypes().get(3);
     internal_static_google_protobuf_EnumValue_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_EnumValue_descriptor,
         new java.lang.String[] { "Name", "Number", "Options", });
     internal_static_google_protobuf_Option_descriptor =
       getDescriptor().getMessageTypes().get(4);
     internal_static_google_protobuf_Option_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_Option_descriptor,
         new java.lang.String[] { "Name", "Value", });
     com.google.protobuf.AnyProto.getDescriptor();
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/UInt32Value.java b/protobuf-api/src/main/java/com/google/protobuf/UInt32Value.java
similarity index 94%
rename from protobuf-sdk/src/main/java/com/google/protobuf/UInt32Value.java
rename to protobuf-api/src/main/java/com/google/protobuf/UInt32Value.java
index b8e69f0..496998a 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/UInt32Value.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/UInt32Value.java
@@ -14,12 +14,12 @@
  * Protobuf type {@code google.protobuf.UInt32Value}
  */
 public final class UInt32Value extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.UInt32Value)
     UInt32ValueOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use UInt32Value.newBuilder() to construct.
-  private UInt32Value(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private UInt32Value(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private UInt32Value() {
@@ -38,7 +38,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.WrappersProto.internal_static_google_protobuf_UInt32Value_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -159,20 +159,20 @@ public static com.google.protobuf.UInt32Value parseFrom(
   }
   public static com.google.protobuf.UInt32Value parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.UInt32Value parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.UInt32Value parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -180,20 +180,20 @@ public static com.google.protobuf.UInt32Value parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.UInt32Value parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.UInt32Value parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -213,7 +213,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -227,7 +227,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.UInt32Value}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.UInt32Value)
       com.google.protobuf.UInt32ValueOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -236,7 +236,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.WrappersProto.internal_static_google_protobuf_UInt32Value_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -249,7 +249,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/UInt32ValueOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/UInt32ValueOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/UInt32ValueOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/UInt32ValueOrBuilder.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/UInt64Value.java b/protobuf-api/src/main/java/com/google/protobuf/UInt64Value.java
similarity index 94%
rename from protobuf-sdk/src/main/java/com/google/protobuf/UInt64Value.java
rename to protobuf-api/src/main/java/com/google/protobuf/UInt64Value.java
index eabc937..054b07c 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/UInt64Value.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/UInt64Value.java
@@ -14,12 +14,12 @@
  * Protobuf type {@code google.protobuf.UInt64Value}
  */
 public final class UInt64Value extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.UInt64Value)
     UInt64ValueOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use UInt64Value.newBuilder() to construct.
-  private UInt64Value(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private UInt64Value(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private UInt64Value() {
@@ -38,7 +38,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.WrappersProto.internal_static_google_protobuf_UInt64Value_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -160,20 +160,20 @@ public static com.google.protobuf.UInt64Value parseFrom(
   }
   public static com.google.protobuf.UInt64Value parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.UInt64Value parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.UInt64Value parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -181,20 +181,20 @@ public static com.google.protobuf.UInt64Value parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.UInt64Value parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.UInt64Value parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -214,7 +214,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -228,7 +228,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.UInt64Value}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.UInt64Value)
       com.google.protobuf.UInt64ValueOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -237,7 +237,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.WrappersProto.internal_static_google_protobuf_UInt64Value_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -250,7 +250,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/UInt64ValueOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/UInt64ValueOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/UInt64ValueOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/UInt64ValueOrBuilder.java
diff --git a/protobuf-api/src/main/java/com/google/protobuf/UnknownFieldSet.java b/protobuf-api/src/main/java/com/google/protobuf/UnknownFieldSet.java
index 10fd7a7..d87ad2b 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/UnknownFieldSet.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/UnknownFieldSet.java
@@ -7,7 +7,6 @@
 
 package com.google.protobuf;
 
-import com.google.protobuf.AbstractMessageLite.Builder.LimitedInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@@ -110,11 +109,11 @@ public void writeTo(CodedOutputStream output) throws IOException {
 
   /**
    * Converts the set to a string in protocol buffer text format. This is just a trivial wrapper
-   * around {@link TextFormat.Printer#printToString(UnknownFieldSet)}.
+   * around {@link TextFormatInternal.printer#printToString(UnknownFieldSet)}.
    */
   @Override
   public String toString() {
-    return TextFormat.printer().printToString(this);
+    return TextFormatInternal.printer().printToString(this);
   }
 
   /**
diff --git a/protobuf-api/src/main/java/com/google/protobuf/UnknownFieldSetLite.java b/protobuf-api/src/main/java/com/google/protobuf/UnknownFieldSetLite.java
index 36c9481..809ac95 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/UnknownFieldSetLite.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/UnknownFieldSetLite.java
@@ -20,7 +20,7 @@
  *
  * @author dweis@google.com (Daniel Weis)
  */
-public final class UnknownFieldSetLite {
+final class UnknownFieldSetLite {
 
   // Arbitrarily chosen.
   // TODO: Tune this number?
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/Value.java b/protobuf-api/src/main/java/com/google/protobuf/Value.java
similarity index 95%
rename from protobuf-sdk/src/main/java/com/google/protobuf/Value.java
rename to protobuf-api/src/main/java/com/google/protobuf/Value.java
index 97dab1a..c56accd 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/Value.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/Value.java
@@ -17,12 +17,12 @@
  * Protobuf type {@code google.protobuf.Value}
  */
 public final class Value extends
-    com.google.protobuf.GeneratedMessageV3 implements
+    com.google.protobuf.GeneratedMessageV3Internal implements
     // @@protoc_insertion_point(message_implements:google.protobuf.Value)
     ValueOrBuilder {
 private static final long serialVersionUID = 0L;
   // Use Value.newBuilder() to construct.
-  private Value(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+  private Value(com.google.protobuf.GeneratedMessageV3Internal.Builder<?> builder) {
     super(builder);
   }
   private Value() {
@@ -41,7 +41,7 @@ protected java.lang.Object newInstance(
   }
 
   @java.lang.Override
-  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+  protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internalGetFieldAccessorTable() {
     return com.google.protobuf.StructProto.internal_static_google_protobuf_Value_fieldAccessorTable
         .ensureFieldAccessorsInitialized(
@@ -53,7 +53,7 @@ protected java.lang.Object newInstance(
   private java.lang.Object kind_;
   public enum KindCase
       implements com.google.protobuf.Internal.EnumLite,
-          com.google.protobuf.AbstractMessage.InternalOneOfEnum {
+          com.google.protobuf.GeneratedMessageV3Internal.InternalOneOfEnum {
     NULL_VALUE(1),
     NUMBER_VALUE(2),
     STRING_VALUE(3),
@@ -371,7 +371,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output)
           2, (double)((java.lang.Double) kind_));
     }
     if (kindCase_ == 3) {
-      com.google.protobuf.GeneratedMessageV3.writeString(output, 3, kind_);
+      com.google.protobuf.GeneratedMessageV3Internal.writeString(output, 3, kind_);
     }
     if (kindCase_ == 4) {
       output.writeBool(
@@ -402,7 +402,7 @@ public int getSerializedSize() {
             2, (double)((java.lang.Double) kind_));
     }
     if (kindCase_ == 3) {
-      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(3, kind_);
+      size += com.google.protobuf.GeneratedMessageV3Internal.computeStringSize(3, kind_);
     }
     if (kindCase_ == 4) {
       size += com.google.protobuf.CodedOutputStream
@@ -542,20 +542,20 @@ public static com.google.protobuf.Value parseFrom(
   }
   public static com.google.protobuf.Value parseFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Value parseFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
   public static com.google.protobuf.Value parseDelimitedFrom(java.io.InputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input);
   }
 
@@ -563,20 +563,20 @@ public static com.google.protobuf.Value parseDelimitedFrom(
       java.io.InputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
   }
   public static com.google.protobuf.Value parseFrom(
       com.google.protobuf.CodedInputStream input)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input);
   }
   public static com.google.protobuf.Value parseFrom(
       com.google.protobuf.CodedInputStream input,
       com.google.protobuf.ExtensionRegistryLite extensionRegistry)
       throws java.io.IOException {
-    return com.google.protobuf.GeneratedMessageV3
+    return com.google.protobuf.GeneratedMessageV3Internal
         .parseWithIOException(PARSER, input, extensionRegistry);
   }
 
@@ -596,7 +596,7 @@ public Builder toBuilder() {
 
   @java.lang.Override
   protected Builder newBuilderForType(
-      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
     Builder builder = new Builder(parent);
     return builder;
   }
@@ -613,7 +613,7 @@ protected Builder newBuilderForType(
    * Protobuf type {@code google.protobuf.Value}
    */
   public static final class Builder extends
-      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      com.google.protobuf.GeneratedMessageV3Internal.Builder<Builder> implements
       // @@protoc_insertion_point(builder_implements:google.protobuf.Value)
       com.google.protobuf.ValueOrBuilder {
     public static final com.google.protobuf.Descriptors.Descriptor
@@ -622,7 +622,7 @@ public static final class Builder extends
     }
 
     @java.lang.Override
-    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    protected com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
         internalGetFieldAccessorTable() {
       return com.google.protobuf.StructProto.internal_static_google_protobuf_Value_fieldAccessorTable
           .ensureFieldAccessorsInitialized(
@@ -635,7 +635,7 @@ private Builder() {
     }
 
     private Builder(
-        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        com.google.protobuf.GeneratedMessageV3Internal.BuilderParent parent) {
       super(parent);
 
     }
@@ -1196,8 +1196,8 @@ public Builder clearBoolValue() {
       return this;
     }
 
-    private com.google.protobuf.SingleFieldBuilderV3<
-        com.google.protobuf.Struct, com.google.protobuf.Struct.Builder, com.google.protobuf.StructOrBuilder> structValueBuilder_;
+    private SingleFieldBuilderV3Internal<
+            Struct, Struct.Builder, StructOrBuilder> structValueBuilder_;
     /**
      * <pre>
      * Represents a structured value.
@@ -1355,15 +1355,15 @@ public com.google.protobuf.StructOrBuilder getStructValueOrBuilder() {
      *
      * <code>.google.protobuf.Struct struct_value = 5;</code>
      */
-    private com.google.protobuf.SingleFieldBuilderV3<
-        com.google.protobuf.Struct, com.google.protobuf.Struct.Builder, com.google.protobuf.StructOrBuilder> 
+    private SingleFieldBuilderV3Internal<
+            Struct, Struct.Builder, StructOrBuilder>
         getStructValueFieldBuilder() {
       if (structValueBuilder_ == null) {
         if (!(kindCase_ == 5)) {
           kind_ = com.google.protobuf.Struct.getDefaultInstance();
         }
-        structValueBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-            com.google.protobuf.Struct, com.google.protobuf.Struct.Builder, com.google.protobuf.StructOrBuilder>(
+        structValueBuilder_ = new SingleFieldBuilderV3Internal<
+                    Struct, Struct.Builder, StructOrBuilder>(
                 (com.google.protobuf.Struct) kind_,
                 getParentForChildren(),
                 isClean());
@@ -1374,8 +1374,8 @@ public com.google.protobuf.StructOrBuilder getStructValueOrBuilder() {
       return structValueBuilder_;
     }
 
-    private com.google.protobuf.SingleFieldBuilderV3<
-        com.google.protobuf.ListValue, com.google.protobuf.ListValue.Builder, com.google.protobuf.ListValueOrBuilder> listValueBuilder_;
+    private SingleFieldBuilderV3Internal<
+            ListValue, ListValue.Builder, ListValueOrBuilder> listValueBuilder_;
     /**
      * <pre>
      * Represents a repeated `Value`.
@@ -1533,15 +1533,15 @@ public com.google.protobuf.ListValueOrBuilder getListValueOrBuilder() {
      *
      * <code>.google.protobuf.ListValue list_value = 6;</code>
      */
-    private com.google.protobuf.SingleFieldBuilderV3<
-        com.google.protobuf.ListValue, com.google.protobuf.ListValue.Builder, com.google.protobuf.ListValueOrBuilder> 
+    private SingleFieldBuilderV3Internal<
+            ListValue, ListValue.Builder, ListValueOrBuilder>
         getListValueFieldBuilder() {
       if (listValueBuilder_ == null) {
         if (!(kindCase_ == 6)) {
           kind_ = com.google.protobuf.ListValue.getDefaultInstance();
         }
-        listValueBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
-            com.google.protobuf.ListValue, com.google.protobuf.ListValue.Builder, com.google.protobuf.ListValueOrBuilder>(
+        listValueBuilder_ = new SingleFieldBuilderV3Internal<
+                    ListValue, ListValue.Builder, ListValueOrBuilder>(
                 (com.google.protobuf.ListValue) kind_,
                 getParentForChildren(),
                 isClean());
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/ValueOrBuilder.java b/protobuf-api/src/main/java/com/google/protobuf/ValueOrBuilder.java
similarity index 100%
rename from protobuf-sdk/src/main/java/com/google/protobuf/ValueOrBuilder.java
rename to protobuf-api/src/main/java/com/google/protobuf/ValueOrBuilder.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/WrappersProto.java b/protobuf-api/src/main/java/com/google/protobuf/WrappersProto.java
similarity index 83%
rename from protobuf-sdk/src/main/java/com/google/protobuf/WrappersProto.java
rename to protobuf-api/src/main/java/com/google/protobuf/WrappersProto.java
index a83a961..0feeeba 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/WrappersProto.java
+++ b/protobuf-api/src/main/java/com/google/protobuf/WrappersProto.java
@@ -18,47 +18,47 @@ public static void registerAllExtensions(
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_DoubleValue_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_DoubleValue_fieldAccessorTable;
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_FloatValue_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_FloatValue_fieldAccessorTable;
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_Int64Value_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_Int64Value_fieldAccessorTable;
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_UInt64Value_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_UInt64Value_fieldAccessorTable;
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_Int32Value_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_Int32Value_fieldAccessorTable;
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_UInt32Value_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_UInt32Value_fieldAccessorTable;
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_BoolValue_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_BoolValue_fieldAccessorTable;
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_StringValue_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_StringValue_fieldAccessorTable;
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_google_protobuf_BytesValue_descriptor;
   static final 
-    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+    com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable
       internal_static_google_protobuf_BytesValue_fieldAccessorTable;
 
   public static com.google.protobuf.Descriptors.FileDescriptor
@@ -89,55 +89,55 @@ public static void registerAllExtensions(
     internal_static_google_protobuf_DoubleValue_descriptor =
       getDescriptor().getMessageTypes().get(0);
     internal_static_google_protobuf_DoubleValue_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_DoubleValue_descriptor,
         new java.lang.String[] { "Value", });
     internal_static_google_protobuf_FloatValue_descriptor =
       getDescriptor().getMessageTypes().get(1);
     internal_static_google_protobuf_FloatValue_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_FloatValue_descriptor,
         new java.lang.String[] { "Value", });
     internal_static_google_protobuf_Int64Value_descriptor =
       getDescriptor().getMessageTypes().get(2);
     internal_static_google_protobuf_Int64Value_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_Int64Value_descriptor,
         new java.lang.String[] { "Value", });
     internal_static_google_protobuf_UInt64Value_descriptor =
       getDescriptor().getMessageTypes().get(3);
     internal_static_google_protobuf_UInt64Value_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_UInt64Value_descriptor,
         new java.lang.String[] { "Value", });
     internal_static_google_protobuf_Int32Value_descriptor =
       getDescriptor().getMessageTypes().get(4);
     internal_static_google_protobuf_Int32Value_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_Int32Value_descriptor,
         new java.lang.String[] { "Value", });
     internal_static_google_protobuf_UInt32Value_descriptor =
       getDescriptor().getMessageTypes().get(5);
     internal_static_google_protobuf_UInt32Value_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_UInt32Value_descriptor,
         new java.lang.String[] { "Value", });
     internal_static_google_protobuf_BoolValue_descriptor =
       getDescriptor().getMessageTypes().get(6);
     internal_static_google_protobuf_BoolValue_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_BoolValue_descriptor,
         new java.lang.String[] { "Value", });
     internal_static_google_protobuf_StringValue_descriptor =
       getDescriptor().getMessageTypes().get(7);
     internal_static_google_protobuf_StringValue_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_StringValue_descriptor,
         new java.lang.String[] { "Value", });
     internal_static_google_protobuf_BytesValue_descriptor =
       getDescriptor().getMessageTypes().get(8);
     internal_static_google_protobuf_BytesValue_fieldAccessorTable = new
-      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+      com.google.protobuf.GeneratedMessageV3Internal.FieldAccessorTable(
         internal_static_google_protobuf_BytesValue_descriptor,
         new java.lang.String[] { "Value", });
   }
diff --git a/protobuf-api/src/main/java/com/google/protobuf/AbstractMessage.java b/protobuf-sdk/src/main/java/com/google/protobuf/AbstractMessage.java
similarity index 94%
rename from protobuf-api/src/main/java/com/google/protobuf/AbstractMessage.java
rename to protobuf-sdk/src/main/java/com/google/protobuf/AbstractMessage.java
index f383625..0d9651e 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/AbstractMessage.java
+++ b/protobuf-sdk/src/main/java/com/google/protobuf/AbstractMessage.java
@@ -30,16 +30,11 @@ public abstract class AbstractMessage
     // TODO: Update GeneratedMessage to parameterize with MessageType and BuilderType.
     extends AbstractMessageLite implements Message {
 
-  @Override
-  public boolean isInitialized() {
-    return MessageReflection.isInitialized(this);
-  }
-
   /**
    * Interface for the parent of a Builder that allows the builder to communicate invalidations back
    * to the parent for use when using nested builders.
    */
-  protected interface BuilderParent {
+  protected interface BuilderParent extends Message.BuilderParent{
 
     /**
      * A builder becomes dirty whenever a field is modified -- including fields in nested builders
@@ -55,9 +50,9 @@ protected interface BuilderParent {
     void markDirty();
   }
 
-  /** Create a nested builder. */
-  protected Message.Builder newBuilderForType(BuilderParent parent) {
-    throw new UnsupportedOperationException("Nested builder is not supported for this type.");
+  @Override
+  public boolean isInitialized() {
+    return MessageReflection.isInitialized(this);
   }
 
   @Override
@@ -446,29 +441,6 @@ protected static UninitializedMessageException newUninitializedMessageException(
       return new UninitializedMessageException(MessageReflection.findMissingFields(message));
     }
 
-    /**
-     * Used to support nested builders and called to mark this builder as clean. Clean builders will
-     * propagate the {@link BuilderParent#markDirty()} event to their parent builders, while dirty
-     * builders will not, as their parents should be dirty already.
-     *
-     * <p>NOTE: Implementations that don't support nested builders don't need to override this
-     * method.
-     */
-    void markClean() {
-      throw new IllegalStateException("Should be overridden by subclasses.");
-    }
-
-    /**
-     * Used to support nested builders and called when this nested builder is no longer used by its
-     * parent builder and should release the reference to its parent builder.
-     *
-     * <p>NOTE: Implementations that don't support nested builders don't need to override this
-     * method.
-     */
-    void dispose() {
-      throw new IllegalStateException("Should be overridden by subclasses.");
-    }
-
     // ===============================================================
     // The following definitions seem to be required in order to make javac
     // not produce weird errors like:
diff --git a/protobuf-api/src/main/java/com/google/protobuf/GeneratedMessage.java b/protobuf-sdk/src/main/java/com/google/protobuf/GeneratedMessage.java
similarity index 99%
rename from protobuf-api/src/main/java/com/google/protobuf/GeneratedMessage.java
rename to protobuf-sdk/src/main/java/com/google/protobuf/GeneratedMessage.java
index d3ff341..bb4f8d6 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/GeneratedMessage.java
+++ b/protobuf-sdk/src/main/java/com/google/protobuf/GeneratedMessage.java
@@ -54,6 +54,11 @@ protected GeneratedMessage(Builder<?> builder) {
     unknownFields = builder.getUnknownFields();
   }
 
+  @Override
+  public boolean isGenerated() {
+    return true;
+  }
+
   @Override
   public Parser<? extends GeneratedMessage> getParserForType() {
     throw new UnsupportedOperationException("This is supposed to be overridden by subclasses.");
@@ -326,7 +331,7 @@ protected interface BuilderParent extends AbstractMessage.BuilderParent {}
   protected abstract Message.Builder newBuilderForType(BuilderParent parent);
 
   @Override
-  protected Message.Builder newBuilderForType(final AbstractMessage.BuilderParent parent) {
+  public Message.Builder newBuilderForType(final Message.BuilderParent parent) {
     return newBuilderForType(
         new BuilderParent() {
           @Override
@@ -359,7 +364,12 @@ protected Builder(BuilderParent builderParent) {
     }
 
     @Override
-    void dispose() {
+    public boolean isGenerated() {
+      return true;
+    }
+
+    @Override
+    public void dispose() {
       builderParent = null;
     }
 
@@ -375,7 +385,7 @@ protected void onBuilt() {
      * and therefore invalidations are needed.
      */
     @Override
-    protected void markClean() {
+    public void markClean() {
       this.isClean = true;
     }
 
@@ -2925,7 +2935,7 @@ public Message.Builder getRepeatedBuilder(
    * @return a SerializedForm of this message
    */
   protected Object writeReplace() throws ObjectStreamException {
-    return new GeneratedMessageLite.SerializedForm(this);
+    return new SerializedForm(this);
   }
 
   /**
diff --git a/protobuf-api/src/main/java/com/google/protobuf/GeneratedMessageV3.java b/protobuf-sdk/src/main/java/com/google/protobuf/GeneratedMessageV3.java
similarity index 99%
rename from protobuf-api/src/main/java/com/google/protobuf/GeneratedMessageV3.java
rename to protobuf-sdk/src/main/java/com/google/protobuf/GeneratedMessageV3.java
index 9c4980f..d2a99ae 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/GeneratedMessageV3.java
+++ b/protobuf-sdk/src/main/java/com/google/protobuf/GeneratedMessageV3.java
@@ -544,7 +544,7 @@ protected interface BuilderParent extends AbstractMessage.BuilderParent {}
 
   /** TODO: generated class should implement this directly */
   @Override
-  protected Message.Builder newBuilderForType(final AbstractMessage.BuilderParent parent) {
+  public Message.Builder newBuilderForType(final Message.BuilderParent parent) {
     return newBuilderForType(
         new BuilderParent() {
           @Override
@@ -589,7 +589,7 @@ protected Builder(BuilderParent builderParent) {
     }
 
     @Override
-    void dispose() {
+    public void dispose() {
       builderParent = null;
     }
 
@@ -605,7 +605,7 @@ protected void onBuilt() {
      * and therefore invalidations are needed.
      */
     @Override
-    protected void markClean() {
+    public void markClean() {
       this.isClean = true;
     }
 
@@ -3251,7 +3251,7 @@ public Message.Builder getRepeatedBuilder(
    * @return a SerializedForm of this message
    */
   protected Object writeReplace() throws ObjectStreamException {
-    return new GeneratedMessageLite.SerializedForm(this);
+    return new SerializedForm(this);
   }
 
   /**
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/JavaFeaturesProto.java b/protobuf-sdk/src/main/java/com/google/protobuf/JavaFeaturesProto.java
index 3b79d74..e5b8ac2 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/JavaFeaturesProto.java
+++ b/protobuf-sdk/src/main/java/com/google/protobuf/JavaFeaturesProto.java
@@ -485,42 +485,36 @@ public static com.google.protobuf.JavaFeaturesProto.JavaFeatures parseFrom(
     }
     public static com.google.protobuf.JavaFeaturesProto.JavaFeatures parseFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
-          .parseWithIOException(PARSER, input);
+      return parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.JavaFeaturesProto.JavaFeatures parseFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
-          .parseWithIOException(PARSER, input, extensionRegistry);
+      return parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     public static com.google.protobuf.JavaFeaturesProto.JavaFeatures parseDelimitedFrom(java.io.InputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
-          .parseDelimitedWithIOException(PARSER, input);
+      return parseDelimitedWithIOException(PARSER, input);
     }
 
     public static com.google.protobuf.JavaFeaturesProto.JavaFeatures parseDelimitedFrom(
         java.io.InputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
-          .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
+      return parseDelimitedWithIOException(PARSER, input, extensionRegistry);
     }
     public static com.google.protobuf.JavaFeaturesProto.JavaFeatures parseFrom(
         com.google.protobuf.CodedInputStream input)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
-          .parseWithIOException(PARSER, input);
+      return parseWithIOException(PARSER, input);
     }
     public static com.google.protobuf.JavaFeaturesProto.JavaFeatures parseFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      return com.google.protobuf.GeneratedMessageV3
-          .parseWithIOException(PARSER, input, extensionRegistry);
+      return parseWithIOException(PARSER, input, extensionRegistry);
     }
 
     @java.lang.Override
diff --git a/protobuf-api/src/main/java/com/google/protobuf/RepeatedFieldBuilderV3.java b/protobuf-sdk/src/main/java/com/google/protobuf/RepeatedFieldBuilderV3.java
similarity index 97%
rename from protobuf-api/src/main/java/com/google/protobuf/RepeatedFieldBuilderV3.java
rename to protobuf-sdk/src/main/java/com/google/protobuf/RepeatedFieldBuilderV3.java
index b36794f..e1dddbe 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/RepeatedFieldBuilderV3.java
+++ b/protobuf-sdk/src/main/java/com/google/protobuf/RepeatedFieldBuilderV3.java
@@ -7,8 +7,6 @@
 
 package com.google.protobuf;
 
-import static com.google.protobuf.Internal.checkNotNull;
-
 import java.util.AbstractList;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -37,13 +35,13 @@
  * @author jonp@google.com (Jon Perlow)
  */
 public class RepeatedFieldBuilderV3<
-        MType extends AbstractMessage,
-        BType extends AbstractMessage.Builder,
+        MType extends Message,
+        BType extends Message.Builder,
         IType extends MessageOrBuilder>
-    implements AbstractMessage.BuilderParent {
+    implements Message.BuilderParent {
 
   // Parent to send changes to.
-  private AbstractMessage.BuilderParent parent;
+  private Message.BuilderParent parent;
 
   // List of messages. Never null. It may be immutable, in which case
   // isMessagesListMutable will be false. See note below.
@@ -71,7 +69,7 @@ public class RepeatedFieldBuilderV3<
   //    was set directly for an index.
 
   // Indicates that we've built a message and so we are now obligated
-  // to dispatch dirty invalidations. See AbstractMessage.BuilderListener.
+  // to dispatch dirty invalidations. See Message.BuilderListener.
   private boolean isClean;
 
   // A view of this builder that exposes a List interface of messages. This is
@@ -104,7 +102,7 @@ public class RepeatedFieldBuilderV3<
   public RepeatedFieldBuilderV3(
       List<MType> messages,
       boolean isMessagesListMutable,
-      AbstractMessage.BuilderParent parent,
+      Message.BuilderParent parent,
       boolean isClean) {
     this.messages = messages;
     this.isMessagesListMutable = isMessagesListMutable;
@@ -367,6 +365,13 @@ public BType addBuilder(MType message) {
     return builder.getBuilder();
   }
 
+  static <T> T checkNotNull(T obj) {
+    if (obj == null) {
+      throw new NullPointerException();
+    }
+    return obj;
+  }
+
   /**
    * Inserts a new builder at the specified position in this list. Shifts the element currently at
    * that position (if any) and any subsequent elements to the right (adds one to their indices).
@@ -551,8 +556,8 @@ private void incrementModCounts() {
    * @param <IType> the common interface for the message and the builder
    */
   private static class MessageExternalList<
-          MType extends AbstractMessage,
-          BType extends AbstractMessage.Builder,
+          MType extends Message,
+          BType extends Message.Builder,
           IType extends MessageOrBuilder>
       extends AbstractList<MType> implements List<MType>, RandomAccess {
 
@@ -585,8 +590,8 @@ void incrementModCount() {
    * @param <IType> the common interface for the message and the builder
    */
   private static class BuilderExternalList<
-          MType extends AbstractMessage,
-          BType extends AbstractMessage.Builder,
+          MType extends Message,
+          BType extends Message.Builder,
           IType extends MessageOrBuilder>
       extends AbstractList<BType> implements List<BType>, RandomAccess {
 
@@ -619,8 +624,8 @@ void incrementModCount() {
    * @param <IType> the common interface for the message and the builder
    */
   private static class MessageOrBuilderExternalList<
-          MType extends AbstractMessage,
-          BType extends AbstractMessage.Builder,
+          MType extends Message,
+          BType extends Message.Builder,
           IType extends MessageOrBuilder>
       extends AbstractList<IType> implements List<IType>, RandomAccess {
 
diff --git a/protobuf-api/src/main/java/com/google/protobuf/SingleFieldBuilderV3.java b/protobuf-sdk/src/main/java/com/google/protobuf/SingleFieldBuilderV3.java
similarity index 93%
rename from protobuf-api/src/main/java/com/google/protobuf/SingleFieldBuilderV3.java
rename to protobuf-sdk/src/main/java/com/google/protobuf/SingleFieldBuilderV3.java
index 0aff2b8..d8d2532 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/SingleFieldBuilderV3.java
+++ b/protobuf-sdk/src/main/java/com/google/protobuf/SingleFieldBuilderV3.java
@@ -7,8 +7,6 @@
 
 package com.google.protobuf;
 
-import static com.google.protobuf.Internal.checkNotNull;
-
 /**
  * {@code SingleFieldBuilderV3} implements a structure that a protocol message uses to hold a single
  * field of another protocol message. It supports the classical use case of setting an immutable
@@ -30,13 +28,13 @@
  * @author jonp@google.com (Jon Perlow)
  */
 public class SingleFieldBuilderV3<
-        MType extends AbstractMessage,
-        BType extends AbstractMessage.Builder,
+        MType extends Message,
+        BType extends Message.Builder,
         IType extends MessageOrBuilder>
-    implements AbstractMessage.BuilderParent {
+    implements Message.BuilderParent {
 
   // Parent to send changes to.
-  private AbstractMessage.BuilderParent parent;
+  private Message.BuilderParent parent;
 
   // Invariant: one of builder or message fields must be non-null.
 
@@ -50,15 +48,22 @@ public class SingleFieldBuilderV3<
   private MType message;
 
   // Indicates that we've built a message and so we are now obligated
-  // to dispatch dirty invalidations. See AbstractMessage.BuilderListener.
+  // to dispatch dirty invalidations. See Message.BuilderListener.
   private boolean isClean;
 
-  public SingleFieldBuilderV3(MType message, AbstractMessage.BuilderParent parent, boolean isClean) {
+  public SingleFieldBuilderV3(MType message, Message.BuilderParent parent, boolean isClean) {
     this.message = checkNotNull(message);
     this.parent = parent;
     this.isClean = isClean;
   }
 
+  static <T> T checkNotNull(T obj) {
+    if (obj == null) {
+      throw new NullPointerException();
+    }
+    return obj;
+  }
+
   public void dispose() {
     // Null out parent so we stop sending it invalidations.
     parent = null;
diff --git a/protobuf-api/src/main/java/com/google/protobuf/TextFormat.java b/protobuf-sdk/src/main/java/com/google/protobuf/TextFormat.java
similarity index 88%
rename from protobuf-api/src/main/java/com/google/protobuf/TextFormat.java
rename to protobuf-sdk/src/main/java/com/google/protobuf/TextFormat.java
index a49919e..e0bfdd2 100644
--- a/protobuf-api/src/main/java/com/google/protobuf/TextFormat.java
+++ b/protobuf-sdk/src/main/java/com/google/protobuf/TextFormat.java
@@ -24,6 +24,8 @@
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+import static com.google.protobuf.TextFormatInternal.*;
+
 /**
  * Provide text parsing and formatting support for proto2 instances. The implementation largely
  * follows text_format.cc.
@@ -2396,176 +2398,11 @@ public static String escapeBytes(byte[] input) {
    */
   public static ByteString unescapeBytes(CharSequence charString)
       throws InvalidEscapeSequenceException {
-    // First convert the Java character sequence to UTF-8 bytes.
-    ByteString input = ByteString.copyFromUtf8(charString.toString());
-    // Then unescape certain byte sequences introduced by ASCII '\\'.  The valid
-    // escapes can all be expressed with ASCII characters, so it is safe to
-    // operate on bytes here.
-    //
-    // Unescaping the input byte array will result in a byte sequence that's no
-    // longer than the input.  That's because each escape sequence is between
-    // two and four bytes long and stands for a single byte.
-    final byte[] result = new byte[input.size()];
-    int pos = 0;
-    for (int i = 0; i < input.size(); i++) {
-      byte c = input.byteAt(i);
-      if (c == '\\') {
-        if (i + 1 < input.size()) {
-          ++i;
-          c = input.byteAt(i);
-          if (isOctal(c)) {
-            // Octal escape.
-            int code = digitValue(c);
-            if (i + 1 < input.size() && isOctal(input.byteAt(i + 1))) {
-              ++i;
-              code = code * 8 + digitValue(input.byteAt(i));
-            }
-            if (i + 1 < input.size() && isOctal(input.byteAt(i + 1))) {
-              ++i;
-              code = code * 8 + digitValue(input.byteAt(i));
-            }
-            // TODO: Check that 0 <= code && code <= 0xFF.
-            result[pos++] = (byte) code;
-          } else {
-            switch (c) {
-              case 'a':
-                result[pos++] = 0x07;
-                break;
-              case 'b':
-                result[pos++] = '\b';
-                break;
-              case 'f':
-                result[pos++] = '\f';
-                break;
-              case 'n':
-                result[pos++] = '\n';
-                break;
-              case 'r':
-                result[pos++] = '\r';
-                break;
-              case 't':
-                result[pos++] = '\t';
-                break;
-              case 'v':
-                result[pos++] = 0x0b;
-                break;
-              case '\\':
-                result[pos++] = '\\';
-                break;
-              case '\'':
-                result[pos++] = '\'';
-                break;
-              case '"':
-                result[pos++] = '\"';
-                break;
-              case '?':
-                result[pos++] = '?';
-                break;
-
-              case 'x':
-                // hex escape
-                int code = 0;
-                if (i + 1 < input.size() && isHex(input.byteAt(i + 1))) {
-                  ++i;
-                  code = digitValue(input.byteAt(i));
-                } else {
-                  throw new InvalidEscapeSequenceException(
-                      "Invalid escape sequence: '\\x' with no digits");
-                }
-                if (i + 1 < input.size() && isHex(input.byteAt(i + 1))) {
-                  ++i;
-                  code = code * 16 + digitValue(input.byteAt(i));
-                }
-                result[pos++] = (byte) code;
-                break;
-
-              case 'u':
-                // Unicode escape
-                ++i;
-                if (i + 3 < input.size()
-                    && isHex(input.byteAt(i))
-                    && isHex(input.byteAt(i + 1))
-                    && isHex(input.byteAt(i + 2))
-                    && isHex(input.byteAt(i + 3))) {
-                  char ch =
-                      (char)
-                          (digitValue(input.byteAt(i)) << 12
-                              | digitValue(input.byteAt(i + 1)) << 8
-                              | digitValue(input.byteAt(i + 2)) << 4
-                              | digitValue(input.byteAt(i + 3)));
-
-                  if (ch >= Character.MIN_SURROGATE && ch <= Character.MAX_SURROGATE) {
-                    throw new InvalidEscapeSequenceException(
-                        "Invalid escape sequence: '\\u' refers to a surrogate");
-                  }
-                  byte[] chUtf8 = Character.toString(ch).getBytes(Internal.UTF_8);
-                  System.arraycopy(chUtf8, 0, result, pos, chUtf8.length);
-                  pos += chUtf8.length;
-                  i += 3;
-                } else {
-                  throw new InvalidEscapeSequenceException(
-                      "Invalid escape sequence: '\\u' with too few hex chars");
-                }
-                break;
-
-              case 'U':
-                // Unicode escape
-                ++i;
-                if (i + 7 >= input.size()) {
-                  throw new InvalidEscapeSequenceException(
-                      "Invalid escape sequence: '\\U' with too few hex chars");
-                }
-                int codepoint = 0;
-                for (int offset = i; offset < i + 8; offset++) {
-                  byte b = input.byteAt(offset);
-                  if (!isHex(b)) {
-                    throw new InvalidEscapeSequenceException(
-                        "Invalid escape sequence: '\\U' with too few hex chars");
-                  }
-                  codepoint = (codepoint << 4) | digitValue(b);
-                }
-                if (!Character.isValidCodePoint(codepoint)) {
-                  throw new InvalidEscapeSequenceException(
-                      "Invalid escape sequence: '\\U"
-                          + input.substring(i, i + 8).toStringUtf8()
-                          + "' is not a valid code point value");
-                }
-                Character.UnicodeBlock unicodeBlock = Character.UnicodeBlock.of(codepoint);
-                if (unicodeBlock != null
-                    && (unicodeBlock.equals(Character.UnicodeBlock.LOW_SURROGATES)
-                        || unicodeBlock.equals(Character.UnicodeBlock.HIGH_SURROGATES)
-                        || unicodeBlock.equals(
-                            Character.UnicodeBlock.HIGH_PRIVATE_USE_SURROGATES))) {
-                  throw new InvalidEscapeSequenceException(
-                      "Invalid escape sequence: '\\U"
-                          + input.substring(i, i + 8).toStringUtf8()
-                          + "' refers to a surrogate code unit");
-                }
-                int[] codepoints = new int[1];
-                codepoints[0] = codepoint;
-                byte[] chUtf8 = new String(codepoints, 0, 1).getBytes(Internal.UTF_8);
-                System.arraycopy(chUtf8, 0, result, pos, chUtf8.length);
-                pos += chUtf8.length;
-                i += 7;
-                break;
-
-              default:
-                throw new InvalidEscapeSequenceException(
-                    "Invalid escape sequence: '\\" + (char) c + '\'');
-            }
-          }
-        } else {
-          throw new InvalidEscapeSequenceException(
-              "Invalid escape sequence: '\\' at end of string.");
-        }
-      } else {
-        result[pos++] = c;
+      try {
+          return TextFormatEscaper.unescapeBytes(charString);
+      } catch (TextFormatEscaper.InvalidEscapeSequenceException e) {
+          throw new TextFormat.InvalidEscapeSequenceException(e.getMessage());
       }
-    }
-
-    return result.length == pos
-        ? ByteString.wrap(result) // This reference has not been out of our control.
-        : ByteString.copyFrom(result, 0, pos);
   }
 
   /**
@@ -2625,128 +2462,4 @@ private static int digitValue(final byte c) {
       return c - 'A' + 10;
     }
   }
-
-  /**
-   * Parse a 32-bit signed integer from the text. Unlike the Java standard {@code
-   * Integer.parseInt()}, this function recognizes the prefixes "0x" and "0" to signify hexadecimal
-   * and octal numbers, respectively.
-   */
-  static int parseInt32(final String text) throws NumberFormatException {
-    return (int) parseInteger(text, true, false);
-  }
-
-  /**
-   * Parse a 32-bit unsigned integer from the text. Unlike the Java standard {@code
-   * Integer.parseInt()}, this function recognizes the prefixes "0x" and "0" to signify hexadecimal
-   * and octal numbers, respectively. The result is coerced to a (signed) {@code int} when returned
-   * since Java has no unsigned integer type.
-   */
-  static int parseUInt32(final String text) throws NumberFormatException {
-    return (int) parseInteger(text, false, false);
-  }
-
-  /**
-   * Parse a 64-bit signed integer from the text. Unlike the Java standard {@code
-   * Integer.parseInt()}, this function recognizes the prefixes "0x" and "0" to signify hexadecimal
-   * and octal numbers, respectively.
-   */
-  static long parseInt64(final String text) throws NumberFormatException {
-    return parseInteger(text, true, true);
-  }
-
-  /**
-   * Parse a 64-bit unsigned integer from the text. Unlike the Java standard {@code
-   * Integer.parseInt()}, this function recognizes the prefixes "0x" and "0" to signify hexadecimal
-   * and octal numbers, respectively. The result is coerced to a (signed) {@code long} when returned
-   * since Java has no unsigned long type.
-   */
-  static long parseUInt64(final String text) throws NumberFormatException {
-    return parseInteger(text, false, true);
-  }
-
-  private static long parseInteger(final String text, final boolean isSigned, final boolean isLong)
-      throws NumberFormatException {
-    int pos = 0;
-
-    boolean negative = false;
-    if (text.startsWith("-", pos)) {
-      if (!isSigned) {
-        throw new NumberFormatException("Number must be positive: " + text);
-      }
-      ++pos;
-      negative = true;
-    }
-
-    int radix = 10;
-    if (text.startsWith("0x", pos)) {
-      pos += 2;
-      radix = 16;
-    } else if (text.startsWith("0", pos)) {
-      radix = 8;
-    }
-
-    final String numberText = text.substring(pos);
-
-    long result = 0;
-    if (numberText.length() < 16) {
-      // Can safely assume no overflow.
-      result = Long.parseLong(numberText, radix);
-      if (negative) {
-        result = -result;
-      }
-
-      // Check bounds.
-      // No need to check for 64-bit numbers since they'd have to be 16 chars
-      // or longer to overflow.
-      if (!isLong) {
-        if (isSigned) {
-          if (result > Integer.MAX_VALUE || result < Integer.MIN_VALUE) {
-            throw new NumberFormatException(
-                "Number out of range for 32-bit signed integer: " + text);
-          }
-        } else {
-          if (result >= (1L << 32) || result < 0) {
-            throw new NumberFormatException(
-                "Number out of range for 32-bit unsigned integer: " + text);
-          }
-        }
-      }
-    } else {
-      BigInteger bigValue = new BigInteger(numberText, radix);
-      if (negative) {
-        bigValue = bigValue.negate();
-      }
-
-      // Check bounds.
-      if (!isLong) {
-        if (isSigned) {
-          if (bigValue.bitLength() > 31) {
-            throw new NumberFormatException(
-                "Number out of range for 32-bit signed integer: " + text);
-          }
-        } else {
-          if (bigValue.bitLength() > 32) {
-            throw new NumberFormatException(
-                "Number out of range for 32-bit unsigned integer: " + text);
-          }
-        }
-      } else {
-        if (isSigned) {
-          if (bigValue.bitLength() > 63) {
-            throw new NumberFormatException(
-                "Number out of range for 64-bit signed integer: " + text);
-          }
-        } else {
-          if (bigValue.bitLength() > 64) {
-            throw new NumberFormatException(
-                "Number out of range for 64-bit unsigned integer: " + text);
-          }
-        }
-      }
-
-      result = bigValue.longValue();
-    }
-
-    return result;
-  }
 }
diff --git a/protobuf-api/src/main/java/com/google/protobuf/TextFormatParseInfoTree.java b/protobuf-sdk/src/main/java/com/google/protobuf/TextFormatParseInfoTree.java
similarity index 100%
rename from protobuf-api/src/main/java/com/google/protobuf/TextFormatParseInfoTree.java
rename to protobuf-sdk/src/main/java/com/google/protobuf/TextFormatParseInfoTree.java
diff --git a/protobuf-api/src/main/java/com/google/protobuf/TextFormatParseLocation.java b/protobuf-sdk/src/main/java/com/google/protobuf/TextFormatParseLocation.java
similarity index 100%
rename from protobuf-api/src/main/java/com/google/protobuf/TextFormatParseLocation.java
rename to protobuf-sdk/src/main/java/com/google/protobuf/TextFormatParseLocation.java
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/compiler/PluginProtos.java b/protobuf-sdk/src/main/java/com/google/protobuf/compiler/PluginProtos.java
index 501218a..6f80eff 100644
--- a/protobuf-sdk/src/main/java/com/google/protobuf/compiler/PluginProtos.java
+++ b/protobuf-sdk/src/main/java/com/google/protobuf/compiler/PluginProtos.java
@@ -4,6 +4,8 @@
 // Protobuf Java Version: 3.25.5
 package com.google.protobuf.compiler;
 
+import java.util.Map;
+
 public final class PluginProtos {
   private PluginProtos() {}
   public static void registerAllExtensions(
@@ -2392,7 +2394,7 @@ public Builder addFileToGenerate(
       public Builder addAllFileToGenerate(
           java.lang.Iterable<java.lang.String> values) {
         ensureFileToGenerateIsMutable();
-        com.google.protobuf.AbstractMessageLite.Builder.addAll(
+        com.google.protobuf.Internal.addAll(
             values, fileToGenerate_);
         bitField0_ |= 0x00000001;
         onChanged();
@@ -2549,7 +2551,7 @@ private void ensureProtoFileIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
+      private com.google.protobuf.compiler.RepeatedFieldBuilderV3Internal<
           com.google.protobuf.DescriptorProtos.FileDescriptorProto, com.google.protobuf.DescriptorProtos.FileDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.FileDescriptorProtoOrBuilder> protoFileBuilder_;
 
       /**
@@ -2901,7 +2903,7 @@ public Builder addAllProtoFile(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.FileDescriptorProto> values) {
         if (protoFileBuilder_ == null) {
           ensureProtoFileIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.Internal.addAll(
               values, protoFile_);
           onChanged();
         } else {
@@ -3161,11 +3163,11 @@ public com.google.protobuf.DescriptorProtos.FileDescriptorProto.Builder addProto
            getProtoFileBuilderList() {
         return getProtoFileFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
+      private com.google.protobuf.compiler.RepeatedFieldBuilderV3Internal<
           com.google.protobuf.DescriptorProtos.FileDescriptorProto, com.google.protobuf.DescriptorProtos.FileDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.FileDescriptorProtoOrBuilder> 
           getProtoFileFieldBuilder() {
         if (protoFileBuilder_ == null) {
-          protoFileBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
+          protoFileBuilder_ = new com.google.protobuf.compiler.RepeatedFieldBuilderV3Internal<
               com.google.protobuf.DescriptorProtos.FileDescriptorProto, com.google.protobuf.DescriptorProtos.FileDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.FileDescriptorProtoOrBuilder>(
                   protoFile_,
                   ((bitField0_ & 0x00000004) != 0),
@@ -3185,7 +3187,7 @@ private void ensureSourceFileDescriptorsIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
+      private com.google.protobuf.compiler.RepeatedFieldBuilderV3Internal<
           com.google.protobuf.DescriptorProtos.FileDescriptorProto, com.google.protobuf.DescriptorProtos.FileDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.FileDescriptorProtoOrBuilder> sourceFileDescriptorsBuilder_;
 
       /**
@@ -3377,7 +3379,7 @@ public Builder addAllSourceFileDescriptors(
           java.lang.Iterable<? extends com.google.protobuf.DescriptorProtos.FileDescriptorProto> values) {
         if (sourceFileDescriptorsBuilder_ == null) {
           ensureSourceFileDescriptorsIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.Internal.addAll(
               values, sourceFileDescriptors_);
           onChanged();
         } else {
@@ -3509,11 +3511,11 @@ public com.google.protobuf.DescriptorProtos.FileDescriptorProto.Builder addSourc
            getSourceFileDescriptorsBuilderList() {
         return getSourceFileDescriptorsFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
+      private com.google.protobuf.compiler.RepeatedFieldBuilderV3Internal<
           com.google.protobuf.DescriptorProtos.FileDescriptorProto, com.google.protobuf.DescriptorProtos.FileDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.FileDescriptorProtoOrBuilder> 
           getSourceFileDescriptorsFieldBuilder() {
         if (sourceFileDescriptorsBuilder_ == null) {
-          sourceFileDescriptorsBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
+          sourceFileDescriptorsBuilder_ = new com.google.protobuf.compiler.RepeatedFieldBuilderV3Internal<
               com.google.protobuf.DescriptorProtos.FileDescriptorProto, com.google.protobuf.DescriptorProtos.FileDescriptorProto.Builder, com.google.protobuf.DescriptorProtos.FileDescriptorProtoOrBuilder>(
                   sourceFileDescriptors_,
                   ((bitField0_ & 0x00000008) != 0),
@@ -3525,7 +3527,7 @@ public com.google.protobuf.DescriptorProtos.FileDescriptorProto.Builder addSourc
       }
 
       private com.google.protobuf.compiler.PluginProtos.Version compilerVersion_;
-      private com.google.protobuf.SingleFieldBuilderV3<
+      private com.google.protobuf.compiler.SingleFieldBuilderV3Internal<
           com.google.protobuf.compiler.PluginProtos.Version, com.google.protobuf.compiler.PluginProtos.Version.Builder, com.google.protobuf.compiler.PluginProtos.VersionOrBuilder> compilerVersionBuilder_;
       /**
        * <pre>
@@ -3667,11 +3669,11 @@ public com.google.protobuf.compiler.PluginProtos.VersionOrBuilder getCompilerVer
        *
        * <code>optional .google.protobuf.compiler.Version compiler_version = 3;</code>
        */
-      private com.google.protobuf.SingleFieldBuilderV3<
+      private com.google.protobuf.compiler.SingleFieldBuilderV3Internal<
           com.google.protobuf.compiler.PluginProtos.Version, com.google.protobuf.compiler.PluginProtos.Version.Builder, com.google.protobuf.compiler.PluginProtos.VersionOrBuilder> 
           getCompilerVersionFieldBuilder() {
         if (compilerVersionBuilder_ == null) {
-          compilerVersionBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
+          compilerVersionBuilder_ = new com.google.protobuf.compiler.SingleFieldBuilderV3Internal<
               com.google.protobuf.compiler.PluginProtos.Version, com.google.protobuf.compiler.PluginProtos.Version.Builder, com.google.protobuf.compiler.PluginProtos.VersionOrBuilder>(
                   getCompilerVersion(),
                   getParentForChildren(),
@@ -5743,7 +5745,7 @@ public Builder setContentBytes(
         }
 
         private com.google.protobuf.DescriptorProtos.GeneratedCodeInfo generatedCodeInfo_;
-        private com.google.protobuf.SingleFieldBuilderV3<
+        private com.google.protobuf.compiler.SingleFieldBuilderV3Internal<
             com.google.protobuf.DescriptorProtos.GeneratedCodeInfo, com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.Builder, com.google.protobuf.DescriptorProtos.GeneratedCodeInfoOrBuilder> generatedCodeInfoBuilder_;
         /**
          * <pre>
@@ -5903,11 +5905,11 @@ public com.google.protobuf.DescriptorProtos.GeneratedCodeInfoOrBuilder getGenera
          *
          * <code>optional .google.protobuf.GeneratedCodeInfo generated_code_info = 16;</code>
          */
-        private com.google.protobuf.SingleFieldBuilderV3<
+        private com.google.protobuf.compiler.SingleFieldBuilderV3Internal<
             com.google.protobuf.DescriptorProtos.GeneratedCodeInfo, com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.Builder, com.google.protobuf.DescriptorProtos.GeneratedCodeInfoOrBuilder> 
             getGeneratedCodeInfoFieldBuilder() {
           if (generatedCodeInfoBuilder_ == null) {
-            generatedCodeInfoBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
+            generatedCodeInfoBuilder_ = new com.google.protobuf.compiler.SingleFieldBuilderV3Internal<
                 com.google.protobuf.DescriptorProtos.GeneratedCodeInfo, com.google.protobuf.DescriptorProtos.GeneratedCodeInfo.Builder, com.google.protobuf.DescriptorProtos.GeneratedCodeInfoOrBuilder>(
                     getGeneratedCodeInfo(),
                     getParentForChildren(),
@@ -7048,7 +7050,7 @@ private void ensureFileIsMutable() {
          }
       }
 
-      private com.google.protobuf.RepeatedFieldBuilderV3<
+      private com.google.protobuf.compiler.RepeatedFieldBuilderV3Internal<
           com.google.protobuf.compiler.PluginProtos.CodeGeneratorResponse.File, com.google.protobuf.compiler.PluginProtos.CodeGeneratorResponse.File.Builder, com.google.protobuf.compiler.PluginProtos.CodeGeneratorResponse.FileOrBuilder> fileBuilder_;
 
       /**
@@ -7180,7 +7182,7 @@ public Builder addAllFile(
           java.lang.Iterable<? extends com.google.protobuf.compiler.PluginProtos.CodeGeneratorResponse.File> values) {
         if (fileBuilder_ == null) {
           ensureFileIsMutable();
-          com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          com.google.protobuf.Internal.addAll(
               values, file_);
           onChanged();
         } else {
@@ -7264,11 +7266,11 @@ public com.google.protobuf.compiler.PluginProtos.CodeGeneratorResponse.File.Buil
            getFileBuilderList() {
         return getFileFieldBuilder().getBuilderList();
       }
-      private com.google.protobuf.RepeatedFieldBuilderV3<
+      private com.google.protobuf.compiler.RepeatedFieldBuilderV3Internal<
           com.google.protobuf.compiler.PluginProtos.CodeGeneratorResponse.File, com.google.protobuf.compiler.PluginProtos.CodeGeneratorResponse.File.Builder, com.google.protobuf.compiler.PluginProtos.CodeGeneratorResponse.FileOrBuilder> 
           getFileFieldBuilder() {
         if (fileBuilder_ == null) {
-          fileBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
+          fileBuilder_ = new com.google.protobuf.compiler.RepeatedFieldBuilderV3Internal<
               com.google.protobuf.compiler.PluginProtos.CodeGeneratorResponse.File, com.google.protobuf.compiler.PluginProtos.CodeGeneratorResponse.File.Builder, com.google.protobuf.compiler.PluginProtos.CodeGeneratorResponse.FileOrBuilder>(
                   file_,
                   ((bitField0_ & 0x00000010) != 0),
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/compiler/RepeatedFieldBuilderV3Internal.java b/protobuf-sdk/src/main/java/com/google/protobuf/compiler/RepeatedFieldBuilderV3Internal.java
new file mode 100644
index 0000000..3390aa9
--- /dev/null
+++ b/protobuf-sdk/src/main/java/com/google/protobuf/compiler/RepeatedFieldBuilderV3Internal.java
@@ -0,0 +1,656 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+
+package com.google.protobuf.compiler;
+
+import com.google.protobuf.Message;
+import com.google.protobuf.MessageOrBuilder;
+
+import java.util.AbstractList;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.RandomAccess;
+
+
+/**
+ * {@code RepeatedFieldBuilderV3} implements a structure that a protocol message uses to hold a
+ * repeated field of other protocol messages. It supports the classical use case of adding immutable
+ * {@link Message}'s to the repeated field and is highly optimized around this (no extra memory
+ * allocations and sharing of immutable arrays). <br>
+ * It also supports the additional use case of adding a {@link Message.Builder} to the repeated
+ * field and deferring conversion of that {@code Builder} to an immutable {@code Message}. In this
+ * way, it's possible to maintain a tree of {@code Builder}'s that acts as a fully read/write data
+ * structure. <br>
+ * Logically, one can think of a tree of builders as converting the entire tree to messages when
+ * build is called on the root or when any method is called that desires a Message instead of a
+ * Builder. In terms of the implementation, the {@code SingleFieldBuilderV3} and {@code
+ * RepeatedFieldBuilderV3} classes cache messages that were created so that messages only need to be
+ * created when some change occurred in its builder or a builder for one of its descendants.
+ *
+ * @param <MType> the type of message for the field
+ * @param <BType> the type of builder for the field
+ * @param <IType> the common interface for the message and the builder
+ * @author jonp@google.com (Jon Perlow)
+ */
+class RepeatedFieldBuilderV3Internal<
+        MType extends Message,
+        BType extends Message.Builder,
+        IType extends MessageOrBuilder>
+    implements Message.BuilderParent {
+
+  // Parent to send changes to.
+  private Message.BuilderParent parent;
+
+  // List of messages. Never null. It may be immutable, in which case
+  // isMessagesListMutable will be false. See note below.
+  private List<MType> messages;
+
+  // Whether messages is an mutable array that can be modified.
+  private boolean isMessagesListMutable;
+
+  // List of builders. May be null, in which case, no nested builders were
+  // created. If not null, entries represent the builder for that index.
+  private List<SingleFieldBuilderV3Internal<MType, BType, IType>> builders;
+
+  // Here are the invariants for messages and builders:
+  // 1. messages is never null and its count corresponds to the number of items
+  //    in the repeated field.
+  // 2. If builders is non-null, messages and builders MUST always
+  //    contain the same number of items.
+  // 3. Entries in either array can be null, but for any index, there MUST be
+  //    either a Message in messages or a builder in builders.
+  // 4. If the builder at an index is non-null, the builder is
+  //    authoritative. This is the case where a Builder was set on the index.
+  //    Any message in the messages array MUST be ignored.
+  // t. If the builder at an index is null, the message in the messages
+  //    list is authoritative. This is the case where a Message (not a Builder)
+  //    was set directly for an index.
+
+  // Indicates that we've built a message and so we are now obligated
+  // to dispatch dirty invalidations. See AbstractMessage.BuilderListener.
+  private boolean isClean;
+
+  // A view of this builder that exposes a List interface of messages. This is
+  // initialized on demand. This is fully backed by this object and all changes
+  // are reflected in it. Access to any item converts it to a message if it
+  // was a builder.
+  private MessageExternalList<MType, BType, IType> externalMessageList;
+
+  // A view of this builder that exposes a List interface of builders. This is
+  // initialized on demand. This is fully backed by this object and all changes
+  // are reflected in it. Access to any item converts it to a builder if it
+  // was a message.
+  private BuilderExternalList<MType, BType, IType> externalBuilderList;
+
+  // A view of this builder that exposes a List interface of the interface
+  // implemented by messages and builders. This is initialized on demand. This
+  // is fully backed by this object and all changes are reflected in it.
+  // Access to any item returns either a builder or message depending on
+  // what is most efficient.
+  private MessageOrBuilderExternalList<MType, BType, IType> externalMessageOrBuilderList;
+
+  /**
+   * Constructs a new builder with an empty list of messages.
+   *
+   * @param messages the current list of messages
+   * @param isMessagesListMutable Whether the messages list is mutable
+   * @param parent a listener to notify of changes
+   * @param isClean whether the builder is initially marked clean
+   */
+  public RepeatedFieldBuilderV3Internal(
+      List<MType> messages,
+      boolean isMessagesListMutable,
+      Message.BuilderParent parent,
+      boolean isClean) {
+    this.messages = messages;
+    this.isMessagesListMutable = isMessagesListMutable;
+    this.parent = parent;
+    this.isClean = isClean;
+  }
+
+  public void dispose() {
+    // Null out parent so we stop sending it invalidations.
+    parent = null;
+  }
+
+  /**
+   * Ensures that the list of messages is mutable so it can be updated. If it's immutable, a copy is
+   * made.
+   */
+  private void ensureMutableMessageList() {
+    if (!isMessagesListMutable) {
+      messages = new ArrayList<MType>(messages);
+      isMessagesListMutable = true;
+    }
+  }
+
+  /**
+   * Ensures that the list of builders is not null. If it's null, the list is created and
+   * initialized to be the same size as the messages list with null entries.
+   */
+  private void ensureBuilders() {
+    if (this.builders == null) {
+      this.builders = new ArrayList<SingleFieldBuilderV3Internal<MType, BType, IType>>(messages.size());
+      for (int i = 0; i < messages.size(); i++) {
+        builders.add(null);
+      }
+    }
+  }
+
+  /**
+   * Gets the count of items in the list.
+   *
+   * @return the count of items in the list.
+   */
+  public int getCount() {
+    return messages.size();
+  }
+
+  /**
+   * Gets whether the list is empty.
+   *
+   * @return whether the list is empty
+   */
+  public boolean isEmpty() {
+    return messages.isEmpty();
+  }
+
+  /**
+   * Get the message at the specified index. If the message is currently stored as a {@code
+   * Builder}, it is converted to a {@code Message} by calling {@link Message.Builder#buildPartial}
+   * on it.
+   *
+   * @param index the index of the message to get
+   * @return the message for the specified index
+   */
+  public MType getMessage(int index) {
+    return getMessage(index, false);
+  }
+
+  /**
+   * Get the message at the specified index. If the message is currently stored as a {@code
+   * Builder}, it is converted to a {@code Message} by calling {@link Message.Builder#buildPartial}
+   * on it.
+   *
+   * @param index the index of the message to get
+   * @param forBuild this is being called for build so we want to make sure we
+   *     SingleFieldBuilderV3.build to send dirty invalidations
+   * @return the message for the specified index
+   */
+  private MType getMessage(int index, boolean forBuild) {
+    if (this.builders == null) {
+      // We don't have any builders -- return the current Message.
+      // This is the case where no builder was created, so we MUST have a
+      // Message.
+      return messages.get(index);
+    }
+
+    SingleFieldBuilderV3Internal<MType, BType, IType> builder = builders.get(index);
+    if (builder == null) {
+      // We don't have a builder -- return the current message.
+      // This is the case where no builder was created for the entry at index,
+      // so we MUST have a message.
+      return messages.get(index);
+
+    } else {
+      return forBuild ? builder.build() : builder.getMessage();
+    }
+  }
+
+  /**
+   * Gets a builder for the specified index. If no builder has been created for that index, a
+   * builder is created on demand by calling {@link Message#toBuilder}.
+   *
+   * @param index the index of the message to get
+   * @return The builder for that index
+   */
+  public BType getBuilder(int index) {
+    ensureBuilders();
+    SingleFieldBuilderV3Internal<MType, BType, IType> builder = builders.get(index);
+    if (builder == null) {
+      MType message = messages.get(index);
+      builder = new SingleFieldBuilderV3Internal<MType, BType, IType>(message, this, isClean);
+      builders.set(index, builder);
+    }
+    return builder.getBuilder();
+  }
+
+  /**
+   * Gets the base class interface for the specified index. This may either be a builder or a
+   * message. It will return whatever is more efficient.
+   *
+   * @param index the index of the message to get
+   * @return the message or builder for the index as the base class interface
+   */
+  @SuppressWarnings("unchecked")
+  public IType getMessageOrBuilder(int index) {
+    if (this.builders == null) {
+      // We don't have any builders -- return the current Message.
+      // This is the case where no builder was created, so we MUST have a
+      // Message.
+      return (IType) messages.get(index);
+    }
+
+    SingleFieldBuilderV3Internal<MType, BType, IType> builder = builders.get(index);
+    if (builder == null) {
+      // We don't have a builder -- return the current message.
+      // This is the case where no builder was created for the entry at index,
+      // so we MUST have a message.
+      return (IType) messages.get(index);
+
+    } else {
+      return builder.getMessageOrBuilder();
+    }
+  }
+
+  static <T> T checkNotNull(T obj) {
+    if (obj == null) {
+      throw new NullPointerException();
+    }
+    return obj;
+  }
+
+  /**
+   * Sets a message at the specified index replacing the existing item at that index.
+   *
+   * @param index the index to set.
+   * @param message the message to set
+   * @return the builder
+   */
+//  @CanIgnoreReturnValue
+  public RepeatedFieldBuilderV3Internal<MType, BType, IType> setMessage(int index, MType message) {
+    checkNotNull(message);
+    ensureMutableMessageList();
+    messages.set(index, message);
+    if (builders != null) {
+      SingleFieldBuilderV3Internal<MType, BType, IType> entry = builders.set(index, null);
+      if (entry != null) {
+        entry.dispose();
+      }
+    }
+    onChanged();
+    incrementModCounts();
+    return this;
+  }
+
+  /**
+   * Appends the specified element to the end of this list.
+   *
+   * @param message the message to add
+   * @return the builder
+   */
+//  @CanIgnoreReturnValue
+  public RepeatedFieldBuilderV3Internal<MType, BType, IType> addMessage(MType message) {
+    checkNotNull(message);
+    ensureMutableMessageList();
+    messages.add(message);
+    if (builders != null) {
+      builders.add(null);
+    }
+    onChanged();
+    incrementModCounts();
+    return this;
+  }
+
+  /**
+   * Inserts the specified message at the specified position in this list. Shifts the element
+   * currently at that position (if any) and any subsequent elements to the right (adds one to their
+   * indices).
+   *
+   * @param index the index at which to insert the message
+   * @param message the message to add
+   * @return the builder
+   */
+//  @CanIgnoreReturnValue
+  public RepeatedFieldBuilderV3Internal<MType, BType, IType> addMessage(int index, MType message) {
+    checkNotNull(message);
+    ensureMutableMessageList();
+    messages.add(index, message);
+    if (builders != null) {
+      builders.add(index, null);
+    }
+    onChanged();
+    incrementModCounts();
+    return this;
+  }
+
+  /**
+   * Appends all of the messages in the specified collection to the end of this list, in the order
+   * that they are returned by the specified collection's iterator.
+   *
+   * @param values the messages to add
+   * @return the builder
+   */
+//  @CanIgnoreReturnValue
+  public RepeatedFieldBuilderV3Internal<MType, BType, IType> addAllMessages(
+      Iterable<? extends MType> values) {
+    for (final MType value : values) {
+      checkNotNull(value);
+    }
+
+    // If we can inspect the size, we can more efficiently add messages.
+    int size = -1;
+    if (values instanceof Collection) {
+      final Collection<?> collection = (Collection<?>) values;
+      if (collection.isEmpty()) {
+        return this;
+      }
+      size = collection.size();
+    }
+    ensureMutableMessageList();
+
+    if (size >= 0 && messages instanceof ArrayList) {
+      ((ArrayList<MType>) messages).ensureCapacity(messages.size() + size);
+    }
+
+    for (MType value : values) {
+      addMessage(value);
+    }
+
+    onChanged();
+    incrementModCounts();
+    return this;
+  }
+
+  /**
+   * Appends a new builder to the end of this list and returns the builder.
+   *
+   * @param message the message to add which is the basis of the builder
+   * @return the new builder
+   */
+  public BType addBuilder(MType message) {
+    ensureMutableMessageList();
+    ensureBuilders();
+    SingleFieldBuilderV3Internal<MType, BType, IType> builder =
+        new SingleFieldBuilderV3Internal<MType, BType, IType>(message, this, isClean);
+    messages.add(null);
+    builders.add(builder);
+    onChanged();
+    incrementModCounts();
+    return builder.getBuilder();
+  }
+
+  /**
+   * Inserts a new builder at the specified position in this list. Shifts the element currently at
+   * that position (if any) and any subsequent elements to the right (adds one to their indices).
+   *
+   * @param index the index at which to insert the builder
+   * @param message the message to add which is the basis of the builder
+   * @return the builder
+   */
+  public BType addBuilder(int index, MType message) {
+    ensureMutableMessageList();
+    ensureBuilders();
+    SingleFieldBuilderV3Internal<MType, BType, IType> builder =
+        new SingleFieldBuilderV3Internal<MType, BType, IType>(message, this, isClean);
+    messages.add(index, null);
+    builders.add(index, builder);
+    onChanged();
+    incrementModCounts();
+    return builder.getBuilder();
+  }
+
+  /**
+   * Removes the element at the specified position in this list. Shifts any subsequent elements to
+   * the left (subtracts one from their indices).
+   *
+   * @param index the index at which to remove the message
+   */
+  public void remove(int index) {
+    ensureMutableMessageList();
+    messages.remove(index);
+    if (builders != null) {
+      SingleFieldBuilderV3Internal<MType, BType, IType> entry = builders.remove(index);
+      if (entry != null) {
+        entry.dispose();
+      }
+    }
+    onChanged();
+    incrementModCounts();
+  }
+
+  /** Removes all of the elements from this list. The list will be empty after this call returns. */
+  public void clear() {
+    messages = Collections.emptyList();
+    isMessagesListMutable = false;
+    if (builders != null) {
+      for (SingleFieldBuilderV3Internal<MType, BType, IType> entry : builders) {
+        if (entry != null) {
+          entry.dispose();
+        }
+      }
+      builders = null;
+    }
+    onChanged();
+    incrementModCounts();
+  }
+
+  /**
+   * Builds the list of messages from the builder and returns them.
+   *
+   * @return an immutable list of messages
+   */
+  public List<MType> build() {
+    // Now that build has been called, we are required to dispatch
+    // invalidations.
+    isClean = true;
+
+    if (!isMessagesListMutable && builders == null) {
+      // We still have an immutable list and we never created a builder.
+      return messages;
+    }
+
+    boolean allMessagesInSync = true;
+    if (!isMessagesListMutable) {
+      // We still have an immutable list. Let's see if any of them are out
+      // of sync with their builders.
+      for (int i = 0; i < messages.size(); i++) {
+        Message message = messages.get(i);
+        SingleFieldBuilderV3Internal<MType, BType, IType> builder = builders.get(i);
+        if (builder != null) {
+          if (builder.build() != message) {
+            allMessagesInSync = false;
+            break;
+          }
+        }
+      }
+      if (allMessagesInSync) {
+        // Immutable list is still in sync.
+        return messages;
+      }
+    }
+
+    // Need to make sure messages is up to date
+    ensureMutableMessageList();
+    for (int i = 0; i < messages.size(); i++) {
+      messages.set(i, getMessage(i, true));
+    }
+
+    // We're going to return our list as immutable so we mark that we can
+    // no longer update it.
+    messages = Collections.unmodifiableList(messages);
+    isMessagesListMutable = false;
+    return messages;
+  }
+
+  /**
+   * Gets a view of the builder as a list of messages. The returned list is live and will reflect
+   * any changes to the underlying builder.
+   *
+   * @return the messages in the list
+   */
+  public List<MType> getMessageList() {
+    if (externalMessageList == null) {
+      externalMessageList = new MessageExternalList<MType, BType, IType>(this);
+    }
+    return externalMessageList;
+  }
+
+  /**
+   * Gets a view of the builder as a list of builders. This returned list is live and will reflect
+   * any changes to the underlying builder.
+   *
+   * @return the builders in the list
+   */
+  public List<BType> getBuilderList() {
+    if (externalBuilderList == null) {
+      externalBuilderList = new BuilderExternalList<MType, BType, IType>(this);
+    }
+    return externalBuilderList;
+  }
+
+  /**
+   * Gets a view of the builder as a list of MessageOrBuilders. This returned list is live and will
+   * reflect any changes to the underlying builder.
+   *
+   * @return the builders in the list
+   */
+  public List<IType> getMessageOrBuilderList() {
+    if (externalMessageOrBuilderList == null) {
+      externalMessageOrBuilderList = new MessageOrBuilderExternalList<MType, BType, IType>(this);
+    }
+    return externalMessageOrBuilderList;
+  }
+
+  /**
+   * Called when a the builder or one of its nested children has changed and any parent should be
+   * notified of its invalidation.
+   */
+  private void onChanged() {
+    if (isClean && parent != null) {
+      parent.markDirty();
+
+      // Don't keep dispatching invalidations until build is called again.
+      isClean = false;
+    }
+  }
+
+  @Override
+  public void markDirty() {
+    onChanged();
+  }
+
+  /**
+   * Increments the mod counts so that an ConcurrentModificationException can be thrown if calling
+   * code tries to modify the builder while its iterating the list.
+   */
+  private void incrementModCounts() {
+    if (externalMessageList != null) {
+      externalMessageList.incrementModCount();
+    }
+    if (externalBuilderList != null) {
+      externalBuilderList.incrementModCount();
+    }
+    if (externalMessageOrBuilderList != null) {
+      externalMessageOrBuilderList.incrementModCount();
+    }
+  }
+
+  /**
+   * Provides a live view of the builder as a list of messages.
+   *
+   * @param <MType> the type of message for the field
+   * @param <BType> the type of builder for the field
+   * @param <IType> the common interface for the message and the builder
+   */
+  private static class MessageExternalList<
+          MType extends Message,
+          BType extends Message.Builder,
+          IType extends MessageOrBuilder>
+      extends AbstractList<MType> implements List<MType>, RandomAccess {
+
+    RepeatedFieldBuilderV3Internal<MType, BType, IType> builder;
+
+    MessageExternalList(RepeatedFieldBuilderV3Internal<MType, BType, IType> builder) {
+      this.builder = builder;
+    }
+
+    @Override
+    public int size() {
+      return this.builder.getCount();
+    }
+
+    @Override
+    public MType get(int index) {
+      return builder.getMessage(index);
+    }
+
+    void incrementModCount() {
+      modCount++;
+    }
+  }
+
+  /**
+   * Provides a live view of the builder as a list of builders.
+   *
+   * @param <MType> the type of message for the field
+   * @param <BType> the type of builder for the field
+   * @param <IType> the common interface for the message and the builder
+   */
+  private static class BuilderExternalList<
+          MType extends Message,
+          BType extends Message.Builder,
+          IType extends MessageOrBuilder>
+      extends AbstractList<BType> implements List<BType>, RandomAccess {
+
+    RepeatedFieldBuilderV3Internal<MType, BType, IType> builder;
+
+    BuilderExternalList(RepeatedFieldBuilderV3Internal<MType, BType, IType> builder) {
+      this.builder = builder;
+    }
+
+    @Override
+    public int size() {
+      return this.builder.getCount();
+    }
+
+    @Override
+    public BType get(int index) {
+      return builder.getBuilder(index);
+    }
+
+    void incrementModCount() {
+      modCount++;
+    }
+  }
+
+  /**
+   * Provides a live view of the builder as a list of builders.
+   *
+   * @param <MType> the type of message for the field
+   * @param <BType> the type of builder for the field
+   * @param <IType> the common interface for the message and the builder
+   */
+  private static class MessageOrBuilderExternalList<
+          MType extends Message,
+          BType extends Message.Builder,
+          IType extends MessageOrBuilder>
+      extends AbstractList<IType> implements List<IType>, RandomAccess {
+
+    RepeatedFieldBuilderV3Internal<MType, BType, IType> builder;
+
+    MessageOrBuilderExternalList(RepeatedFieldBuilderV3Internal<MType, BType, IType> builder) {
+      this.builder = builder;
+    }
+
+    @Override
+    public int size() {
+      return this.builder.getCount();
+    }
+
+    @Override
+    public IType get(int index) {
+      return builder.getMessageOrBuilder(index);
+    }
+
+    void incrementModCount() {
+      modCount++;
+    }
+  }
+}
diff --git a/protobuf-sdk/src/main/java/com/google/protobuf/compiler/SingleFieldBuilderV3Internal.java b/protobuf-sdk/src/main/java/com/google/protobuf/compiler/SingleFieldBuilderV3Internal.java
new file mode 100644
index 0000000..da0cd92
--- /dev/null
+++ b/protobuf-sdk/src/main/java/com/google/protobuf/compiler/SingleFieldBuilderV3Internal.java
@@ -0,0 +1,219 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+
+package com.google.protobuf.compiler;
+
+import com.google.protobuf.Message;
+import com.google.protobuf.MessageOrBuilder;
+
+/**
+ * {@code SingleFieldBuilderV3} implements a structure that a protocol message uses to hold a single
+ * field of another protocol message. It supports the classical use case of setting an immutable
+ * {@link Message} as the value of the field and is highly optimized around this.
+ *
+ * <p>It also supports the additional use case of setting a {@link Message.Builder} as the field and
+ * deferring conversion of that {@code Builder} to an immutable {@code Message}. In this way, it's
+ * possible to maintain a tree of {@code Builder}'s that acts as a fully read/write data structure.
+ * <br>
+ * Logically, one can think of a tree of builders as converting the entire tree to messages when
+ * build is called on the root or when any method is called that desires a Message instead of a
+ * Builder. In terms of the implementation, the {@code SingleFieldBuilderV3} and {@code
+ * RepeatedFieldBuilderV3} classes cache messages that were created so that messages only need to be
+ * created when some change occurred in its builder or a builder for one of its descendants.
+ *
+ * @param <MType> the type of message for the field
+ * @param <BType> the type of builder for the field
+ * @param <IType> the common interface for the message and the builder
+ * @author jonp@google.com (Jon Perlow)
+ */
+class SingleFieldBuilderV3Internal<
+        MType extends Message,
+        BType extends Message.Builder,
+        IType extends MessageOrBuilder>
+    implements Message.BuilderParent {
+
+  // Parent to send changes to.
+  private Message.BuilderParent parent;
+
+  // Invariant: one of builder or message fields must be non-null.
+
+  // If set, this is the case where we are backed by a builder. In this case,
+  // message field represents a cached message for the builder (or null if
+  // there is no cached message).
+  private BType builder;
+
+  // If builder is non-null, this represents a cached message from the builder.
+  // If builder is null, this is the authoritative message for the field.
+  private MType message;
+
+  // Indicates that we've built a message and so we are now obligated
+  // to dispatch dirty invalidations. See AbstractMessage.BuilderListener.
+  private boolean isClean;
+
+  public SingleFieldBuilderV3Internal(MType message, Message.BuilderParent parent, boolean isClean) {
+    this.message = checkNotNull(message);
+    this.parent = parent;
+    this.isClean = isClean;
+  }
+
+  public void dispose() {
+    // Null out parent so we stop sending it invalidations.
+    parent = null;
+  }
+
+  /**
+   * Get the message for the field. If the message is currently stored as a {@code Builder}, it is
+   * converted to a {@code Message} by calling {@link Message.Builder#buildPartial} on it. If no
+   * message has been set, returns the default instance of the message.
+   *
+   * @return the message for the field
+   */
+  @SuppressWarnings("unchecked")
+  public MType getMessage() {
+    if (message == null) {
+      // If message is null, the invariant is that we must be have a builder.
+      message = (MType) builder.buildPartial();
+    }
+    return message;
+  }
+
+  /**
+   * Builds the message and returns it.
+   *
+   * @return the message
+   */
+  public MType build() {
+    // Now that build has been called, we are required to dispatch
+    // invalidations.
+    isClean = true;
+    return getMessage();
+  }
+
+  /**
+   * Gets a builder for the field. If no builder has been created yet, a builder is created on
+   * demand by calling {@link Message#toBuilder}.
+   *
+   * @return The builder for the field
+   */
+  @SuppressWarnings("unchecked")
+  public BType getBuilder() {
+    if (builder == null) {
+      // builder.mergeFrom() on a fresh builder
+      // does not create any sub-objects with independent clean/dirty states,
+      // therefore setting the builder itself to clean without actually calling
+      // build() cannot break any invariants.
+      builder = (BType) message.newBuilderForType();
+      builder.mergeFrom(message); // no-op if message is the default message
+//      builder.markClean();
+    }
+    return builder;
+  }
+
+  /**
+   * Gets the base class interface for the field. This may either be a builder or a message. It will
+   * return whatever is more efficient.
+   *
+   * @return the message or builder for the field as the base class interface
+   */
+  @SuppressWarnings("unchecked")
+  public IType getMessageOrBuilder() {
+    if (builder != null) {
+      return (IType) builder;
+    } else {
+      return (IType) message;
+    }
+  }
+
+  /**
+   * Sets a message for the field replacing any existing value.
+   *
+   * @param message the message to set
+   * @return the builder
+   */
+  // Comment out because CanIgnoreReturnValue is package private to com.google.protobuf
+//  @CanIgnoreReturnValue
+  public SingleFieldBuilderV3Internal<MType, BType, IType> setMessage(MType message) {
+    this.message = checkNotNull(message);
+    if (builder != null) {
+//      builder.dispose();
+      builder = null;
+    }
+    onChanged();
+    return this;
+  }
+
+  /**
+   * Merges the field from another field.
+   *
+   * @param value the value to merge from
+   * @return the builder
+   */
+//  @CanIgnoreReturnValue
+  public SingleFieldBuilderV3Internal<MType, BType, IType> mergeFrom(MType value) {
+    if (builder == null && message == message.getDefaultInstanceForType()) {
+      message = value;
+    } else {
+      getBuilder().mergeFrom(value);
+    }
+    onChanged();
+    return this;
+  }
+
+  /**
+   * Clears the value of the field.
+   *
+   * @return the builder
+   */
+  @SuppressWarnings("unchecked")
+//  @CanIgnoreReturnValue
+  public SingleFieldBuilderV3Internal<MType, BType, IType> clear() {
+    message =
+        (MType)
+            (message != null
+                ? message.getDefaultInstanceForType()
+                : builder.getDefaultInstanceForType());
+    if (builder != null) {
+//      builder.dispose();
+      builder = null;
+    }
+    onChanged();
+    // After clearing, parent is dirty, but this field builder is now clean and any changes should
+    // trickle up.
+    isClean = true;
+    return this;
+  }
+
+  /**
+   * Called when a the builder or one of its nested children has changed and any parent should be
+   * notified of its invalidation.
+   */
+  private void onChanged() {
+    // If builder is null, this is the case where onChanged is being called
+    // from setMessage or clear.
+    if (builder != null) {
+      message = null;
+    }
+    if (isClean && parent != null) {
+      parent.markDirty();
+
+      // Don't keep dispatching invalidations until build is called again.
+      isClean = false;
+    }
+  }
+
+  static <T> T checkNotNull(T obj) {
+    if (obj == null) {
+      throw new NullPointerException();
+    }
+    return obj;
+  }
+  
+  @Override
+  public void markDirty() {
+    onChanged();
+  }
+}