Drop unbounded cache

Author: jack-berg

api/incubator/src/main/java/io/opentelemetry/api/incubator/common/ExtendedAttributeKey.java

@@ -50,7 +50,7 @@ default AttributeKey<T> asAttributeKey() {
   /** Return an ExtendedAttributeKey equivalent to the {@code attributeKey}. */
   // TODO (jack-berg): remove once AttributeKey.asExtendedAttributeKey is available
   static <T> ExtendedAttributeKey<T> fromAttributeKey(AttributeKey<T> attributeKey) {
-    return InternalExtendedAttributeKeyImpl.fromAttributeKey(attributeKey);
+    return InternalExtendedAttributeKeyImpl.toExtendedAttributeKey(attributeKey);
   }
 
   /** Returns a new ExtendedAttributeKey for String valued attributes. */

api/incubator/src/main/java/io/opentelemetry/api/incubator/internal/InternalExtendedAttributeKeyImpl.java

@@ -11,7 +11,6 @@
 import io.opentelemetry.api.incubator.common.ExtendedAttributeType;
 import io.opentelemetry.api.internal.InternalAttributeKeyImpl;
 import java.nio.charset.StandardCharsets;
-import java.util.concurrent.ConcurrentHashMap;
 import javax.annotation.Nullable;
 
 /**
@@ -20,9 +19,6 @@
  */
 public final class InternalExtendedAttributeKeyImpl<T> implements ExtendedAttributeKey<T> {
 
-  private static final ConcurrentHashMap<AttributeKey<?>, ExtendedAttributeKey<?>>
-      ATTRIBUTE_KEY_CACHE = new ConcurrentHashMap<>();
-
   private final ExtendedAttributeType type;
   private final String key;
   private final int hashCode;
@@ -47,17 +43,6 @@ public static <T> ExtendedAttributeKey<T> create(
     return new InternalExtendedAttributeKeyImpl<>(type, key != null ? key : "");
   }
 
-  /**
-   * Return an {@link ExtendedAttributeKey} equivalent to the {@code attributeKey}, caching entries
-   * in {@link #ATTRIBUTE_KEY_CACHE}.
-   */
-  @SuppressWarnings("unchecked")
-  public static <T> ExtendedAttributeKey<T> fromAttributeKey(AttributeKey<T> attributeKey) {
-    return (ExtendedAttributeKey<T>)
-        ATTRIBUTE_KEY_CACHE.computeIfAbsent(
-            attributeKey, InternalExtendedAttributeKeyImpl::toExtendedAttributeKey);
-  }
-
   @Override
   public ExtendedAttributeType getType() {
     return type;