Question

I am using valueUnbound method of HttpSessionBindingListener to release lock(an entry from the database), before session is about to expire:

@Override

public void valueUnbound(HttpSessionBindingEvent event) {
  String user = (String) event.getSession().getAttribute("currentUsr");
  removeLock(user);
}

When the lock is set, I am setting up the username as a session variable.
I need this “username” in my remove lock method. But the getAttribute is throwing an exception:

java.lang.IllegalStateException: getAttribute: Session already invalidated

I need help in getting the session variable?? or is there any other way to get the username?

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No, since session has been invalidated.

Although, I figured out the solution, I am setting the attribute via servlet context in
valueBound method and getting it through the : event.getSession().getServletContext().getAttribute(“cUser”);

it works fine. Thank You EJP

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I got your point EJP, you are right , I am making it complex, I can get it from event.getValue() . +1 to your answer, Thank You.

Answer 1

Although, I figured out the solution, I am setting the attribute via servlet context in valueBound method and getting it through the : event.getSession().getServletContext().getAttribute("cUser");

So.. You are storing session scoped data in the application scope. Do you realize that this way the data is shared among all visitors of the webapp? Visitor X would then see the attribute set by visitor Y which has visited the website at a later moment. It makes the problem only worse.

Anyway, as to the concrete problem, as the exception message is trying to tell you, the session has already been invalidated at that point. There are two ways to solve this:

1. Make currentUsr a property of the class which is implementing HttpSessionBindingListener, so that you don’t need to grab it as a distinct session attribute.

2. Use a HttpSessionListener instead. The sessionDestroyed() method is called right before invalidation, so you should still have access to all attributes.