Prabhu,
Jason Hunter explains 2 techniques for this kind of auto refresh requirements. 1. Client pull and 2. Server Push.
Client pull - means the client (the browser) automatically makes a request for every *** seconds period.
Server push - means the server sends the reponse automatically to the browser.
I grabbed the code for client pull from Jason Hunter's site for you. This example shows , the client makes a request to every 10 secs to a servlet automatically and diplays the time. See it online here.
http://www.servlets.com/servlet/ClientPull Here is the code.
For the other tech (Server push) please go through the examples and find out. I try to post when I come across that. Here is the examples link
http://www.servlets.com/jsp/examples/index.html regds
maha anna