code: @Override
    public synchronized void onNext(final RuntimeStop runtimeStop) {
      LOG.log(Level.FINEST, "HttpRuntimeStopHandler: {0}", runtimeStop);
      try {
        httpServer.stop();
        LOG.log(Level.FINEST, "HttpRuntimeStopHandler complete.");
      } catch (final Exception e) {
        LOG.log(Level.SEVERE, "HttpRuntimeStopHandler cannot stop the Server. {0}", e);
      }
    }
docs: Override EventHandler<RuntimeStop>.
  
  @param runtimeStop