code: public final synchronized void refresh( HttpServletRequest request, HttpServletResponse response )
      {
          PerRequestState prevState = setPerRequestState( new PerRequestState( request, response, null ) );
  
          try
          {
              onRefresh();
          }
          finally
          {
              setPerRequestState( prevState );
          }
      }
docs: Called on this object for non-lookup (refresh) requests.  This is a framework-invoked method that should not
  normally be called directly.