Add missing interfaces to emulated classes

user/super/com/google/gwt/emul/java/io/PrintStream.java

@@ -19,7 +19,7 @@
  * See <a href="http://java.sun.com/j2se/1.5.0/docs/api/java/io/PrintStream.html">the official Java
  * API doc</a> for details.
  */
-public class PrintStream extends FilterOutputStream {
+public class PrintStream extends FilterOutputStream implements Appendable {
 
   /** Indicates whether or not this PrintStream has incurred an error. */
   private boolean ioError = false;
@@ -195,4 +195,22 @@ protected void clearError() {
   private void newline() {
     print('\n');
   }
+
+  @Override
+  public Appendable append(CharSequence csq) {
+    print(csq);
+    return this;
+  }
+
+  @Override
+  public Appendable append(CharSequence csq, int start, int end) {
+    print(csq.subSequence(start, end));
+    return this;
+  }
+
+  @Override
+  public Appendable append(char c) {
+    print(c);
+    return this;
+  }
 }

user/super/com/google/gwt/emul/java/io/Reader.java

@@ -18,7 +18,7 @@
 /**
  * Reads a stream of characters.
  */
-public abstract class Reader {
+public abstract class Reader implements Closeable {
   /**
    * The maximum buffer size to incrementally read in {@link #skip}.
    */
@@ -27,6 +27,7 @@ public abstract class Reader {
   /**
    * Closes the reader, and releases any associated resources.
    */
+  @Override
   public abstract void close() throws IOException;
 
   /**

user/super/com/google/gwt/emul/java/lang/Boolean.java

@@ -18,13 +18,14 @@
 import static javaemul.internal.InternalPreconditions.checkNotNull;
 
 import java.io.Serializable;
+import java.lang.constant.Constable;
 import javaemul.internal.JsUtils;
 import jsinterop.annotations.JsMethod;
 
 /**
  * Wraps native <code>boolean</code> as an object.
  */
-public final class Boolean implements Comparable<Boolean>, Serializable {
+public final class Boolean implements Comparable<Boolean>, Serializable, Constable {
 
   public static final Boolean FALSE = false;
   public static final Boolean TRUE = true;

user/super/com/google/gwt/emul/java/lang/Byte.java

@@ -15,10 +15,12 @@
  */
 package java.lang;
 
+import java.lang.constant.Constable;
+
 /**
  * Wraps native <code>byte</code> as an object.
  */
-public final class Byte extends Number implements Comparable<Byte> {
+public final class Byte extends Number implements Comparable<Byte>, Constable {
 
   public static final byte MIN_VALUE = (byte) 0x80;
   public static final byte MAX_VALUE = (byte) 0x7F;

user/super/com/google/gwt/emul/java/lang/Class.java

@@ -17,6 +17,7 @@
 
 import com.google.gwt.core.client.JavaScriptObject;
 
+import java.lang.constant.Constable;
 import java.lang.reflect.Type;
 import javaemul.internal.annotations.DoNotInline;
 
@@ -29,7 +30,7 @@
  *
  * @param <T> the type of the object
  */
-public final class Class<T> implements Type {
+public final class Class<T> implements Type, Constable {
 
   private static final int PRIMITIVE = 0x00000001;
   private static final int INTERFACE = 0x00000002;

user/super/com/google/gwt/emul/java/lang/Enum.java

@@ -21,6 +21,7 @@
 import com.google.gwt.core.client.JavaScriptObject;
 
 import java.io.Serializable;
+import java.lang.constant.Constable;
 import jsinterop.annotations.JsIgnore;
 import jsinterop.annotations.JsNonNull;
 import jsinterop.annotations.JsType;
@@ -31,7 +32,7 @@
  * @param <E>
  */
 @JsType
-public abstract class Enum<E extends Enum<E>> implements Comparable<E>, Serializable {
+public abstract class Enum<E extends Enum<E>> implements Comparable<E>, Serializable, Constable {
 
   @JsIgnore
   public static <T extends Enum<T>> T valueOf(Class<T> enumType, String name) {

user/super/com/google/gwt/emul/java/lang/Float.java

@@ -15,12 +15,14 @@
  */
 package java.lang;
 
+import java.lang.constant.Constable;
+import java.lang.constant.ConstantDesc;
 import javaemul.internal.JsUtils;
 
 /**
  * Wraps a primitive <code>float</code> as an object.
  */
-public final class Float extends Number implements Comparable<Float> {
+public final class Float extends Number implements Comparable<Float>, Constable, ConstantDesc {
   public static final float MAX_VALUE = 3.4028235e+38f;
   public static final float MIN_VALUE = 1.4e-45f;
   public static final int MAX_EXPONENT = 127;

user/super/com/google/gwt/emul/java/lang/Integer.java

@@ -15,13 +15,15 @@
  */
 package java.lang;
 
+import java.lang.constant.Constable;
+import java.lang.constant.ConstantDesc;
 import javaemul.internal.JsUtils;
 import javaemul.internal.annotations.HasNoSideEffects;
 
 /**
  * Wraps a primitive <code>int</code> as an object.
  */
-public final class Integer extends Number implements Comparable<Integer> {
+public final class Integer extends Number implements Comparable<Integer>, Constable, ConstantDesc {
 
   public static final int MAX_VALUE = 0x7fffffff;
   public static final int MIN_VALUE = 0x80000000;

user/super/com/google/gwt/emul/java/lang/Long.java

@@ -15,11 +15,13 @@
  */
 package java.lang;
 
+import java.lang.constant.Constable;
+import java.lang.constant.ConstantDesc;
 import javaemul.internal.LongUtils;
 import javaemul.internal.annotations.HasNoSideEffects;
 
 /** Wraps a primitive <code>long</code> as an object. */
-public final class Long extends Number implements Comparable<Long> {
+public final class Long extends Number implements Comparable<Long>, Constable, ConstantDesc {
 
   /** Use nested class to avoid clinit on outer. */
   static class BoxedValues {

user/super/com/google/gwt/emul/java/lang/String.java

@@ -24,6 +24,8 @@
 
 import java.io.Serializable;
 import java.io.UnsupportedEncodingException;
+import java.lang.constant.Constable;
+import java.lang.constant.ConstantDesc;
 import java.nio.charset.Charset;
 import java.nio.charset.UnsupportedCharsetException;
 import java.util.Comparator;
@@ -55,7 +57,7 @@
 // Needed to have constructors not fail compilation internally at Google
 @SuppressWarnings({ "ReturnValueIgnored", "unusable-by-js" })
 public final class String implements Comparable<String>, CharSequence,
-    Serializable {
+    Serializable, Constable, ConstantDesc {
   /* TODO(jat): consider whether we want to support the following methods;
    *
    * <ul>

user/super/com/google/gwt/emul/java/lang/StringBuffer.java

@@ -23,7 +23,8 @@
  * This class is an exact clone of {@link StringBuilder} except for the name.
  * Any change made to one should be mirrored in the other.
  */
-public final class StringBuffer extends AbstractStringBuilder {
+public final class StringBuffer extends AbstractStringBuilder
+    implements Comparable<StringBuffer> {
 
   public StringBuffer() {
     super("");
@@ -187,4 +188,9 @@ public StringBuffer reverse() {
     reverse0();
     return this;
   }
+
+  @Override
+  public int compareTo(StringBuffer other) {
+    return toString().compareTo(other.toString());
+  }
 }

user/super/com/google/gwt/emul/java/lang/StringBuilder.java

@@ -23,7 +23,8 @@
  * This class is an exact clone of {@link StringBuffer} except for the name.
  * Any change made to one should be mirrored in the other.
  */
-public final class StringBuilder extends AbstractStringBuilder {
+public final class StringBuilder extends AbstractStringBuilder
+    implements Comparable<StringBuilder> {
 
   public StringBuilder() {
     super("");
@@ -187,4 +188,9 @@ public StringBuilder reverse() {
     reverse0();
     return this;
   }
+
+  @Override
+  public int compareTo(StringBuilder other) {
+    return toString().compareTo(other.toString());
+  }
 }

user/super/com/google/gwt/emul/java/lang/constant/Constable.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2025 GWT Project Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package java.lang.constant;
+
+public interface Constable {
+}

user/super/com/google/gwt/emul/java/lang/constant/ConstantDesc.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2026 GWT Project Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package java.lang.constant;
+
+public interface ConstantDesc {
+}

user/super/com/google/gwt/emul/java/util/BitSet.java

@@ -34,7 +34,7 @@
  * public static BitSet valueOf(ByteBuffer)
  * public static BitSet valueOf(LongBuffer)
  */
-public class BitSet {
+public class BitSet implements Cloneable {
   private static final int WORD_MASK = 0x7fffffff;
   private static final int BITS_PER_WORD = 31;
 

user/super/com/google/gwt/emul/java/util/EnumMap.java

@@ -28,7 +28,7 @@
  * @param <K> key type
  * @param <V> value type
  */
-public class EnumMap<K extends Enum<K>, V> extends AbstractMap<K, V> {
+public class EnumMap<K extends Enum<K>, V> extends AbstractMap<K, V> implements Cloneable {
 
   private final class EntrySet extends AbstractSet<Entry<K, V>> {
 

user/super/com/google/gwt/emul/java/util/EnumSet.java

@@ -31,7 +31,7 @@
  *
  * @param <E> enumeration type
  */
-public abstract class EnumSet<E extends Enum<E>> extends AbstractSet<E> {
+public abstract class EnumSet<E extends Enum<E>> extends AbstractSet<E> implements Cloneable {
 
   /**
    * Implemented via sparse array since the set size is finite. Iteration takes