http session object,ejb session bean

What is difference b/w HttpSession object,Stateful Session bean in EJB to hold state info?Why is Stateful session bean adavantageous?

Actually these days almost no one uses stateful sessions beans, most people use stateless session beans. So the HTTP session is really the best way to store temporary session in a J2EE application.

If you want a longer answer go on Google and look up stateful session beans... the reviews aren't very positive.

it is almost incorrect that "Actually these days almost no one uses stateful sessions beans" , almost everywhere that people need to keep track of a session in an enterprise application they use statefull session beans.
indeed an stateful session bean fulfill many requirements that you may need in an enterprise application , like session persistence... :-) .

people use stateless session beans when they do not need to keep track of a session and they have similar response for every request that they need to process.

http sessions are very good when we have a web front end , but at least when we have a fat client we will use Session beans, application servers provide very good replication over session beans , so again you will use a session bean when you are going to use application servers extra features.