code: public static boolean isValidJsonStrict(Reader in) throws IOException {
  		try {
  			new JSONParser(MODE_RFC4627).parse(in, FakeMapper.DEFAULT);
  			return true;
  		} catch (ParseException e) {
  			return false;
  		}
  	}
docs: Check RFC4627 Json Syntax from input Reader
  
  @return if the input is valid