code: public void stop() {
      if (server == null) {
        return;
      }
  
      logger.fine("Shutting down STP connection listener");
      monitor.remove(server);
      try {
        server.close();
      } catch (IOException e) {
        // ignored
      } finally {
        server = null;
      }
    }
docs: Shuts down and cleans up the STP connection to Opera.