code: public void stopResponder() {
      LOGGER.info("Force shutdown of Responder [" + _runtimeId + "]");
      _shutdownHook.start();
      Runtime.getRuntime().removeShutdownHook(_shutdownHook);
    }
docs: Close the socket and tell the processing loop to terminate. This is a
  forced shutdown rather then a natural shutdown. A natural shutdown happens
  when the shutdown hook fires when the VM exists. This method forces all
  that to happen. This is done to allow multiple Responders to be created and
  destroyed during a single VM session. Necessary for various testing and
  management procedures.