how to test if a session is valid

["radha ganapathy" <radha_ganapathy@xxxxxxxxxxx>]

Hi,
I have an application deployed as ear file on weblogic6.1. The app has a 
class implementing HttpSessionAttributesListener.
On successful login, I use setMaxInactiveInterval to set the timeout to 5 
minutes.
I use setAttribute to  put the user id in the session with a tag of 
'userid'.

In the doPost() of all my servlets, I have the following code to check if 
session is valid. but even if i leave my session inactive for more than 5 
minutes, this function returns true because the attributer 'userid' is still 
there.

What is wrong in this method?

protected boolean isSessionValid(HttpServletRequest req)
   {
     HttpSession oSession = req.getSession();
     System.out.println("oSession.getMaxInactiveInterval() : " + 
oSession.getMaxInactiveInterval());
     System.out.println("oSession.getLastAccessedTime() : " + 
oSession.getLastAccessedTime());
     String strUserID = (String)oSession.getAttribute("userid");
     System.out.println("oSession.getAttribute(\"userid\"): " + strUserID);
     if ( (strUserID == null) || (strUserID.length() == 0) ) {
       return false;
     } else {
       return true;
     }
   }


Here is sample output from the print statements in that method :
oSession.getMaxInactiveInterval() : 300
oSession.getLastAccessedTime() : 1102540440997
oSession.getAttribute("userid"): test123
oSession.getMaxInactiveInterval() : 300
oSession.getLastAccessedTime() : 1102544848815
oSession.getAttribute("userid"): test123

thanx,
radha.