title: can valueUnbound() method of HttpSessionBindingListener be used to get informed whenever a session is about to be destroyed?
body: <p>The <strong>valueUnbound()</strong> method of <strong>HttpSessionBindingListener</strong> is used to inform the attribute's object which was added as an attribute in an Http session, that it has been removed from the session. In "<strong>HeadFirst JSP and Servlets</strong>", they say that it can also be indirectly used to notify the application whenever a session is about to be destroyed, along with <strong>HttpSessionListener.sessionDestroyed</strong>. How is that possible ?</p>