Automated rollback of commit 05e5107.

PiperOrigin-RevId: 638409590

java/core/src/main/java/com/google/protobuf/GeneratedMessage.java

@@ -1028,38 +1028,21 @@ public boolean isInitialized() {
      * numbers, but we must write them in canonical (sorted by field number) order. ExtensionWriter
      * helps us write individual ranges of extensions at once.
      */
-    protected interface ExtensionWriter {
-      public void writeUntil(final int end, final CodedOutputStream output) throws IOException;
-    }
-
-    // Singleton instance so we can avoid allocating a new one for each message serialization.
-    private static final NoOpExtensionWriter NO_OP_EXTENSION_WRITER = new NoOpExtensionWriter();
-
-    /** No-op implementation that writes nothing, for messages with no extensions. */
-    private static final class NoOpExtensionWriter implements ExtensionWriter {
-      @Override
-      public void writeUntil(final int end, final CodedOutputStream output) {
-        // no-op
-      }
-    }
-
-    /** Implementation that writes extensions from the FieldSet, for messages with extensions. */
-    private final class FieldSetExtensionWriter implements ExtensionWriter {
+    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 FieldSetExtensionWriter(final boolean messageSetWireFormat) {
+      private ExtensionWriter(final boolean messageSetWireFormat) {
         if (iter.hasNext()) {
           next = iter.next();
         }
         this.messageSetWireFormat = messageSetWireFormat;
       }
 
-      @Override
       public void writeUntil(final int end, final CodedOutputStream output) throws IOException {
         while (next != null && next.getKey().getNumber() < end) {
           FieldDescriptor descriptor = next.getKey();
@@ -1093,19 +1076,11 @@ public void writeUntil(final int end, final CodedOutputStream output) throws IOE
     }
 
     protected ExtensionWriter newExtensionWriter() {
-      // Avoid allocation in the common case of no extensions.
-      if (extensions.isEmpty()) {
-        return NO_OP_EXTENSION_WRITER;
-      }
-      return new FieldSetExtensionWriter(false);
+      return new ExtensionWriter(false);
     }
 
     protected ExtensionWriter newMessageSetExtensionWriter() {
-      // Avoid allocation in the common case of no extensions.
-      if (extensions.isEmpty()) {
-        return NO_OP_EXTENSION_WRITER;
-      }
-      return new FieldSetExtensionWriter(true);
+      return new ExtensionWriter(true);
     }
 
     /** Called by subclasses to compute the size of extensions. */

src/google/protobuf/compiler/java/full/message.cc

@@ -587,13 +587,15 @@ void ImmutableMessageGenerator::GenerateMessageSerializationMethods(
     if (descriptor_->options().message_set_wire_format()) {
       printer->Print(
           "com.google.protobuf.GeneratedMessage\n"
-          "  .ExtendableMessage.ExtensionWriter\n"
-          "    extensionWriter = newMessageSetExtensionWriter();\n");
+          "  .ExtendableMessage<$classname$>.ExtensionWriter\n"
+          "    extensionWriter = newMessageSetExtensionWriter();\n",
+          "classname", name_resolver_->GetImmutableClassName(descriptor_));
     } else {
       printer->Print(
           "com.google.protobuf.GeneratedMessage\n"
-          "  .ExtendableMessage.ExtensionWriter\n"
-          "    extensionWriter = newExtensionWriter();\n");
+          "  .ExtendableMessage<$classname$>.ExtensionWriter\n"
+          "    extensionWriter = newExtensionWriter();\n",
+          "classname", name_resolver_->GetImmutableClassName(descriptor_));
     }
   }