diff --git a/src/google/protobuf/util/internal/protostream_objectwriter.cc b/src/google/protobuf/util/internal/protostream_objectwriter.cc
index f9ddbf326..7f6f3c354 100644
--- a/src/google/protobuf/util/internal/protostream_objectwriter.cc
+++ b/src/google/protobuf/util/internal/protostream_objectwriter.cc
@@ -1541,8 +1541,10 @@ bool ProtoStreamObjectWriter::IsMap(const google::protobuf::Field& field) {
   const google::protobuf::Type* field_type =
       typeinfo_->GetType(field.type_url());
 
+  // TODO(xiaofeng): Unify option names.
   return GetBoolOptionOrDefault(field_type->options(),
-                                "google.protobuf.MessageOptions.map_entry", false);
+                                "google.protobuf.MessageOptions.map_entry", false) ||
+         GetBoolOptionOrDefault(field_type->options(), "map_entry", false);
 }
 
 void ProtoStreamObjectWriter::WriteTag(const google::protobuf::Field& field) {
diff --git a/src/google/protobuf/util/json_util_test.cc b/src/google/protobuf/util/json_util_test.cc
index 8399b4080..6686416ca 100644
--- a/src/google/protobuf/util/json_util_test.cc
+++ b/src/google/protobuf/util/json_util_test.cc
@@ -47,6 +47,7 @@ namespace {
 using proto3::FOO;
 using proto3::BAR;
 using proto3::TestMessage;
+using proto3::TestMap;
 
 static const char kTypeUrlPrefix[] = "type.googleapis.com";
 
@@ -146,6 +147,16 @@ TEST_F(JsonUtilTest, ParseMessage) {
   EXPECT_EQ(96, m.repeated_message_value(1).value());
 }
 
+TEST_F(JsonUtilTest, ParseMap) {
+  TestMap message;
+  (*message.mutable_string_map())["hello"] = 1234;
+  JsonOptions options;
+  EXPECT_EQ("{\"stringMap\":{\"hello\":1234}}", ToJson(message, options));
+  TestMap other;
+  ASSERT_TRUE(FromJson(ToJson(message, options), &other));
+  EXPECT_EQ(message.DebugString(), other.DebugString());
+}
+
 typedef pair<char*, int> Segment;
 // A ZeroCopyOutputStream that writes to multiple buffers.
 class SegmentedZeroCopyOutputStream : public io::ZeroCopyOutputStream {