code: public void requestFailed (Exception cause)
      {
          Object[] args = _args != null ? ArrayUtil.append(_args, cause) : new Object[] { cause };
          if (_slogger != null) {
              _slogger.warning(_errorText, args);
          } else if (_jlogger != null) {
              _jlogger.log(Level.WARNING, Logger.format(_errorText, args), cause);
          } else {
              System.err.println(Logger.format(_errorText, args));
          }
      }
docs: from interface ResultListener