JsonFormat.merge throw a exception when a 'message' field in json is null

[haoyanzhang]

message A {
//xxx
}
message B {
optional A a=0;
}

B.Builder builder = B.newBuild();
new JsonFormat().merge("{a: null}", ExtensionRegistry.getEmptyRegistry(), builder);

Will throw exception like
Exception in thread "main" com.googlecode.protobuf.format.JsonFormat$ParseException: 1:13: Expected "{"

version 1.4

[harrylee2015]

这个问题你解决了吗？是不是要换低版本包，我可能也遇到同样问题了，json转proto报一样的错误