code: protected synchronized void doStop() throws Exception
      {
          try
          {
              // Stop servlets
              super.doStop();
  
              // Stop filters
              for (int i= _filters.size(); i-- > 0;)
              {
                  FilterHolder holder= (FilterHolder)_filters.get(i);
                  holder.stop();
              }
          }
          finally
          {
              _webApplicationContext= null;
              _sessionListeners= null;
              _requestListeners= null;
              _requestAttributeListeners= null;
              _contextAttributeListeners= null;
          }
      }
docs: /* ------------------------------------------------------------