1 files changed, 33 insertions, 11 deletions
diff --git a/src/google/protobuf/compiler/java/java_message_lite.cc b/src/google/protobuf/compiler/java/java_message_lite.cc
index 29b4f98b..f2c9d71e 100644
--- a/src/google/protobuf/compiler/java/java_message_lite.cc
+++ b/src/google/protobuf/compiler/java/java_message_lite.cc
@@ -69,6 +69,14 @@ using internal::WireFormat;
 using internal::WireFormatLite;
 
 namespace {
+bool EnableExperimentalRuntimeForLite() {
+#ifdef PROTOBUF_EXPERIMENT
+  return PROTOBUF_EXPERIMENT;
+#else   // PROTOBUF_EXPERIMENT
+  return false;
+#endif  // !PROTOBUF_EXPERIMENT
+}
+
 bool GenerateHasBits(const Descriptor* descriptor) {
   return SupportFieldPresence(descriptor->file()) ||
       HasRepeatedFields(descriptor);
@@ -361,14 +369,14 @@ void ImmutableMessageLiteGenerator::Generate(io::Printer* printer) {
   printer->Indent();
   printer->Indent();
 
-  printer->Print(
-    "case IS_INITIALIZED: {\n");
+  printer->Print("case IS_INITIALIZED: {\n");
   printer->Indent();
   GenerateDynamicMethodIsInitialized(printer);
   printer->Outdent();
 
+  printer->Print("}\n");
+
   printer->Print(
-    "}\n"
     "case MAKE_IMMUTABLE: {\n");
 
   printer->Indent();
@@ -383,13 +391,15 @@ void ImmutableMessageLiteGenerator::Generate(io::Printer* printer) {
   GenerateDynamicMethodNewBuilder(printer);
   printer->Outdent();
 
-  printer->Print(
-    "}\n"
-    "case VISIT: {\n");
+  if (!EnableExperimentalRuntimeForLite()) {
+    printer->Print(
+        "}\n"
+        "case VISIT: {\n");
 
-  printer->Indent();
-  GenerateDynamicMethodVisit(printer);
-  printer->Outdent();
+    printer->Indent();
+    GenerateDynamicMethodVisit(printer);
+    printer->Outdent();
+  }
 
   printer->Print(
     "}\n"
@@ -470,6 +480,17 @@ void ImmutableMessageLiteGenerator::Generate(io::Printer* printer) {
     "}\n"
     "\n",
     "classname", descriptor_->name());
+  if (EnableExperimentalRuntimeForLite()) {
+    // Register the default instance in a map. This map will be used by
+    // experimental runtime to lookup default instance given a class instance
+    // without using Java reflection.
+    printer->Print(
+        "static {\n"
+        "  com.google.protobuf.GeneratedMessageLite.registerDefaultInstance(\n"
+        "    $classname$.class, DEFAULT_INSTANCE);\n"
+        "}\n",
+        "classname", descriptor_->name());
+  }
   printer->Print(
       "public static $classname$ getDefaultInstance() {\n"
       "  return DEFAULT_INSTANCE;\n"
@@ -502,6 +523,7 @@ void ImmutableMessageLiteGenerator::Generate(io::Printer* printer) {
   printer->Print("}\n\n");
 }
 
+
 // ===================================================================
 
 void ImmutableMessageLiteGenerator::
@@ -708,10 +730,10 @@ void ImmutableMessageLiteGenerator::GenerateSerializeOneExtensionRange(
 void ImmutableMessageLiteGenerator::GenerateBuilder(io::Printer* printer) {
   printer->Print(
     "public static Builder newBuilder() {\n"
-    "  return DEFAULT_INSTANCE.toBuilder();\n"
+    "  return DEFAULT_INSTANCE.createBuilder();\n"
     "}\n"
     "public static Builder newBuilder($classname$ prototype) {\n"
-    "  return DEFAULT_INSTANCE.toBuilder().mergeFrom(prototype);\n"
+    "  return DEFAULT_INSTANCE.createBuilder(prototype);\n"
     "}\n"
     "\n",
     "classname", name_resolver_->GetImmutableClassName(descriptor_));