session expiry

[Amin Mohammed-Coleman]

Hi,

I am currently working on a JSP search component which uses sessions. The default session timeout is set at 30mins. In my JSP page I implement the following:

if (request.isRequestedSessionIdValid() != true)
{
 throw new IllegalStateException();
}

This exception is caught in an error page which states:
"Session has Expired. Please start again".

The problem is when i test this page after 30mins I get a NullPointerException. After debugging I've found out that certain objects that I have placed in the session have disappeared. So I modified my code to do the following:

if (request.isRequestedSessionIdValid()!=true && session.getAttribute("object") ==null)
{
 throw new IllegalStateException();
}

However, this does not solve the problem in that after 30mins I still get NullPointerException and not displaying "Session has expired". In the error page I catch IllegalStateException and print out the session expiry statement.

Can anyone tell me what other criteria I should look for when the session has expired?

Thanks
[ June 07, 2005: Message edited by: amz ]

[Ben Souther]

Just check to see if the object stored in session is null.
If so, either redirect or forward to the login page.

[Amin Mohammed-Coleman]

Originally posted by Ben Souther:
Just check to see if the object stored in session is null.
If so, either redirect or forward to the login page.

I have been trying to implement this, but unfortunately I still get NullPointerException rather than session expiry page appearing.

Thanks

[Nathan Pruett]

"amz" -

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JavaRanch Naming Policy. User names cannot be obviously fake and must constist of a first name and a last name.

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Thanks! and welcome to the JavaRanch!

[Ben Souther]

Originally posted by amz:


I have been trying to implement this, but unfortunately I still get NullPointerException rather than session expiry page appearing.

Thanks

A call to sendRedirect or forward doesn't stop the execution of a servlet or jsp on it's own.
Try adding a "return;" statement just after your redirect or forward.

if(null == session.getAttribute("userBean")){
  response.sendRedirect("login_page.jsp");
  return;
}

[Amin Mohammed-Coleman]

Originally posted by Ben Souther:

if(null == session.getAttribute("userBean")){
  response.sendRedirect("login_page.jsp");
  return;
}

The problem is that the my jsp page is a component inside another jsp page therefore i cannot use response.sendRedirect().

I have tried null == session.getAttribute("userBean")...but for some reason it still throws a NullPointerException.

[Henrique Sousa]

Originally posted by Amin Mohammed-Coleman:
I have tried null == session.getAttribute("userBean")...but for some reason it still throws a NullPointerException.

If your NullPointerException comes from that line, it probably means the session object is null, perhaps because you got it with getSession passing false[I] as argument.
One way out of it is to check if [I]session is null.

if (session == null) {
    // session has been invalidated or wrong j_sessionid used in request
}

Regards

[Amin Mohammed-Coleman]

Originally posted by Henrique Sousa:

if (session == null) {
    // session has been invalidated or wrong j_sessionid used in request
}

Hi,
ok...I'm at the point of tearing my hair out! I've basically tried the following scenarios:

if session == null
if session.isRequestedSessionIdValid() !=true
if session.getAttribute("object") ==null

and i still get NullPointerException.

anymore advice will be much appreciated.

Thanks

[Ben Souther]

Post the line of code that is throwing the NullPointerException (NPE).
Also post the stack trace.

[kirtikumar patel]

hi!
had you been used isErrorpage=true flag in jsp page or not?if not,plz try it