code: public synchronized void stop(boolean graceful)
          throws InterruptedException
      {
          boolean ov=_gracefulStop;
          try
          {
              _gracefulStop=graceful;
              stop();
          }
          finally
          {
              _gracefulStop=ov;
          }
      }
docs: Stop all listeners then all contexts.
  @param graceful If true and statistics are on for a context,
  then this method will wait for requestsActive to go to zero
  before stopping that context.