State of HttpSession instance after timeout?

Question

What makes the HttpSession instance expire as after time-out also when checked

 if(session!=null){

        System.out.println("The instance is not null");
        }else{
        System.out.println("The instance is null");
        }

each time the if-block is executed.

Answer 1

• For expiring the session, use session.invalidate(). This will ensure that your session is expired.
• Even if session is invalidated, it doesn't necessarily mean it is null

Answer 2

If you use HttpServletRequest.getSession(false), then a HttpSession object does not get created, if it is invalid.

In that case, session can be null.