How to maintain Session

Hi Freinds!
In one interview interviewer ask me a question about "How to maintain a scope of session throughout the application?"
At that time I gave some wayword answer

So please give me some information about this.
Thanks in Advanced!

At that time I gave some wayword answer

Sounds like a wayward question.
Did he explain it at all?

if i am not mistaken it maintains automatically throughout the application.

Well My wayword answer was "If we dosen't initialize or create another new session then that session will maintain throuout" Then he ask me "How to retrive the value of first page on last page without storing it in a database?"
at that time I became clueless! So can you explain me this?

Sounds like he wanted you to explain how to bind objects (variables) to session scope and then retrieve them in another request.

http://java.sun.com/j2ee/sdk_1.3/techdocs/api/javax/servlet/http/HttpSession.html

Pay particular attention to setAttribute and getAttribute.
Understanding variable scoping is a pretty fundamental requirement in Servlet/JSP programming.
[ April 22, 2005: Message edited by: Ben Souther ]