code: public void shutdown() {
      LOGGER.info("Responder shutting down: [" + _runtimeId + "]");
      for (Transport t : _transports) {
        try {
          t.shutdown();
        } catch (TransportException e) {
          LOGGER.warn( "Error shutting down transport: [" + t.transportName() + "]", e);
        }
      }
    }
docs: This will shutdown the listening socket and remove the responder from the
  multicast group. Part of the natural life cycle. It also will end the run
  loop of the responder automatically - it will interrupt any read operation
  going on and exit the run loop.