Session Binding/Oracle 9iAS

Question

Hi,
I am experiencing a problem with session binding whilst using Oracle 9iAS. The same code works without problem in Tomcat. For some reason in Oracle, the session seems to invalidate before the valueUnbound() is called? (The session is being added correctly but is never removed from my list of active users)
Can anyone help with this or know of a workaround? Thanks in advance.
I am using the following code:
In log in class we add to the session:
session.setAttribute("user",userID);
session.setAttribute("userList",userList.getInstance());
In log out class we just do following:
session.invalidate();
And in the servlet we have a timeout set as follows:
session.setMaxInactiveInterval(60);
import javax.servlet.http.*;
import java.util.*;
* Class maintains the number or ACTIVE sessions. 
* valueBound()  -  when user logs on, the session is added to this list
* valueUnbound() - when user logs off or is timed out, user is removed from list
* getUserCount() - returns number of users with active sessions
public class userList implements HttpSessionBindingListener
  private static userList list = null;     
  private Set users = new HashSet();     
  private userList()
  {          super();     }     
  public static userList getInstance()
    if (list == null)          
    {          list = new userList();          }          
    return list;     
  public void valueBound(HttpSessionBindingEvent sbe)
    System.out.println(sbe.getSession().getAttribute("user"));
    users.add(sbe.getSession().getAttribute("user")); //Add the session     
    System.out.println(" ----- adding the user to the active list ----- ");
  public void valueUnbound(HttpSessionBindingEvent sbe)
    System.out.println(" ----- trying to remove user from active list ----- ");
    try
    { users.remove(sbe.getSession().getAttribute("user"));     }  //Remove the session
    catch (Exception e)
    { System.out.println("session was already invalidated"); }
  public synchronized int getUserCount()
    return users.size(); //Returns the no of live user sessions     
  public synchronized Set getUserList()
    return users; //Returns the names of live user sessions     

Answer 1

Thanks. We have tried this but it still falls over when doing the valueUnbound(). The error is as follows:
session was already invalidated java.lang.IllegalStateException: Session was invalidated
So it seems Oracle is invalidating my session before getting to the method. This would be ok as long as the session is cleaned up, but we are using connection pooling and this is the only way I know to maintain a list of our active users. Obviously we cant rely on them logging out and we need to know when the session times out.
Can anyone help here with another way of knowing when the session times out?