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Bookmark "Logout problem." Watch "Logout problem." New topic

Logout problem.

Yogendra Joshi
Ranch Hand

Joined: Apr 04, 2006
Posts: 213
Hi friends,

I have been reading Kathy Sierra Head First JSP/Servlets book and i am very happy to learn it the way the chapters are organized.

Recently i completed Conversational State chapter and tried having my hands on Sessions in Web in which i am stuck at 1 point, i created the following.

1. Login.jsp which would have a username and password.
2. which would set the request parameter to session attribute and this LoginAction class would forward the request using RequestDispatcher to result.jsp.
3. result.jsp has a Greeting for the user registered saying "Welcome, " and it works like a dream.

Now my problem.

Result.jsp has a link to logout.jsp, Below is the code of result.jsp

and then logout.jsp has the following code :

What i was expecting was it would show "Welcome,Guest" because when i said session.invalidate, it made the session as null and on checker.jsp i am checking for session==null , however it showed Welcome null. I am not sure why session.invalidate() on Logout.jsp did not return null.

Can you all please help me.

Below is checker.jsp for reference.

Yogendra N Joshi.
[ December 25, 2008: Message edited by: Yogendra Joshi ]

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Arie Prastowo

Joined: Apr 20, 2008
Posts: 22
I think that is happen because in JSP, session is never null. It is an implicit object, so I guess HttpServletRequest.getSession() is always called.

Arie Prastowo

SCJP 5.0<br />Use the power of mind
Bauke Scholtz
Ranch Hand

Joined: Oct 08, 2006
Posts: 2458
You need HttpSession#isNew() rather than testing it against null.

That said, your logout.jsp is bogus. Check your appserver logs. There is an IllegalStateException in it.
Yogendra Joshi
Ranch Hand

Joined: Apr 04, 2006
Posts: 213
Hi All,

Thanks a lot for your valuable suggestion , session.isNew did the work. It now correctly returns WElcome Guest.

I would also check if session==null had IllegalStateException in the logs.

I agree. Here's the link:
subject: Logout problem.
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