code: @Override public void stop() {
          lock.lock();
          try {
              if (process != null) {
                  destroyProcess();
              }
              process = null;
          } finally {
              lock.unlock();
          }
      }
docs: Stops this service is it is currently running. This method will attempt to block until the
  server has been fully shutdown.
  
  @see #start()