code: public static ResponseStatus valueOf(int code) {
      code = code & 0xFFFF; // convert negative shorts to unsigned
      if (code < 256) {
        ResponseStatus status = values[code];
        if (status != null) {
          return status;
        }
      }
      return new ResponseStatus(code);
    }
docs: Returns the ResponseStatus with the given status code. For recognized codes, this method
  is guaranteed to always return the same ResponseStatus instance, so it's safe to use == for equality checks
  against the pre-defined constants.