diff --git a/examples/README.md b/examples/README.md
index 430568e14e..64e6d907ba 100644
--- a/examples/README.md
+++ b/examples/README.md
@@ -28,7 +28,7 @@ Then you can run the built binary:
     $ bazel-bin/add_person_cpp addressbook.data
 
 To use protobuf in your own bazel project, please follow instructions in the
-[BUILD](BUILD) file and [WORKSPACE](WORKSPACE) file.
+[BUILD.bazel](BUILD.bazel) file and [WORKSPACE](WORKSPACE) file.
 
 ## Build the example using make
 
diff --git a/java/core/src/main/java/com/google/protobuf/ExtensionSchemaLite.java b/java/core/src/main/java/com/google/protobuf/ExtensionSchemaLite.java
index 880ee29ffa..ca0095123f 100644
--- a/java/core/src/main/java/com/google/protobuf/ExtensionSchemaLite.java
+++ b/java/core/src/main/java/com/google/protobuf/ExtensionSchemaLite.java
@@ -255,12 +255,40 @@ final class ExtensionSchemaLite extends ExtensionSchema<ExtensionDescriptor> {
             value = reader.readString();
             break;
           case GROUP:
+            if (!extension.isRepeated()) {
+              Object oldValue = extensions.getField(extension.descriptor);
+              if (oldValue instanceof GeneratedMessageLite) {
+                Schema extSchema = Protobuf.getInstance().schemaFor(oldValue);
+                if (!((GeneratedMessageLite<?, ?>) oldValue).isMutable()) {
+                  Object newValue = extSchema.newInstance();
+                  extSchema.mergeFrom(newValue, oldValue);
+                  extensions.setField(extension.descriptor, newValue);
+                  oldValue = newValue;
+                }
+                reader.mergeGroupField(oldValue, extSchema, extensionRegistry);
+                return unknownFields;
+              }
+            }
             value =
                 reader.readGroup(
                     extension.getMessageDefaultInstance().getClass(), extensionRegistry);
             break;
 
           case MESSAGE:
+            if (!extension.isRepeated()) {
+              Object oldValue = extensions.getField(extension.descriptor);
+              if (oldValue instanceof GeneratedMessageLite) {
+                Schema extSchema = Protobuf.getInstance().schemaFor(oldValue);
+                if (!((GeneratedMessageLite<?, ?>) oldValue).isMutable()) {
+                  Object newValue = extSchema.newInstance();
+                  extSchema.mergeFrom(newValue, oldValue);
+                  extensions.setField(extension.descriptor, newValue);
+                  oldValue = newValue;
+                }
+                reader.mergeMessageField(oldValue, extSchema, extensionRegistry);
+                return unknownFields;
+              }
+            }
             value =
                 reader.readMessage(
                     extension.getMessageDefaultInstance().getClass(), extensionRegistry);
diff --git a/java/core/src/main/java/com/google/protobuf/FieldSet.java b/java/core/src/main/java/com/google/protobuf/FieldSet.java
index 21dd8d229f..4f514c224e 100644
--- a/java/core/src/main/java/com/google/protobuf/FieldSet.java
+++ b/java/core/src/main/java/com/google/protobuf/FieldSet.java
@@ -123,6 +123,11 @@ final class FieldSet<T extends FieldSet.FieldDescriptorLite<T>> {
     if (isImmutable) {
       return;
     }
+    for (Object value : fields.values()) {
+      if (value instanceof GeneratedMessageLite) {
+        ((GeneratedMessageLite<?, ?>) value).makeImmutable();
+      }
+    }
     fields.makeImmutable();
     isImmutable = true;
   }
diff --git a/third_party/googletest b/third_party/googletest
index 4c9a3bb62b..5ec7f0c4a1 160000
--- a/third_party/googletest
+++ b/third_party/googletest
@@ -1 +1 @@
-Subproject commit 4c9a3bb62bf3ba1f1010bf96f9c8ed767b363774
+Subproject commit 5ec7f0c4a113e2f18ac2c6cc7df51ad6afc24081