code: @Override
      protected void doStart() throws Exception
      {
          log.info("starting...");
          super.doStart();
          _client = newClient(_serverString);
          if (_client == null)
          {
              throw new IllegalStateException("newClient(" + _serverString + ") returns null.");
          }
          log.info("use " + _client.getClass().getSimpleName() + " as client factory.");
          _client.establish();
          log.info("started.");
      }
docs: /* ------------------------------------------------------------