Thanks, scott! Let me know servlet context can get a notification.
I looked at that bug following the URL. I think it is a bug only on single machine. Web server and app server are on the same machine. For distributed environment, whether it is a bug depends on the sequence which admin shuts down the web server and app server following. If admin shuts down web server before app server, then that it not a bug. However if admin shuts down app server firstly, it is still a bug except that when app server is shutting down, it notices web server and then web server terminates automatically.