Salam Raja,
When the web container that is running the servlet (
Tomcat for ex) sends data to the HTTP client, it uses an opened connection with the HTTP client. That connection is ALWAYS opened by the HTTP client when it requests a resource from the server. So having the web container/servlet send data to the client without having this later request any resource DOES NOT MAKE SENSE (think about TCP at client side that would drop silently all incoming segments that don't belong to any opened connection).
However, you can embed a little script within the HTML page that runs at client side and that sends requests to your servlet periodically behind the scenes. This way, your servlet would reply periodically in a normal way.
regards
[ June 25, 2002: Message edited by: Omar IRAQI ]