code: public void handleFailure (Exception error)
      {
          if (error instanceof InvocationException) {
              _listener.requestFailed(error.getMessage());
          } else {
              if (_args != null) {
                  log.warning(getFailureMessage(), ArrayUtil.append(_args, error));
              } else {
                  log.warning(getFailureMessage(), error);
              }
              _listener.requestFailed(InvocationCodes.INTERNAL_ERROR);
          }
      }
docs: Handles the failure case by logging the error and reporting an internal error to the
  listener.