communication problem in chat application.....Please help!!

Hi all,
I have developed a simple chat application based on http, i.e.
using applet and servlets and a bit of html.
Now i need to broadcast the messages to members sitting in a particular chat room. This is where my problem lies.
I got no idea as to how i could redirect the messages to selected members of the chat app without using rmi or sockets.
The chat application is based on the example given in O'Reilly's
Java Servlet Programming.
Any help is welcomed and will be appreciated.
Thanks everyone !
Bye.

That's the problem with http-based applications. It's a connectionless protocol. You're right, I do not think there is any way to do it via server-side push via http (well there is, that book shows a server-side push but it'll spawn lots of threads). So in the end, most http-based apps are client-polling apps. I looked at Sun's JSDT (shared data something) and maybe that's the solution but it seemed too complicated for me!