Detach- Event not fired on idle session when heartbeats missing

Vaadin 6 / 7 / 8
1

Hi all,
I’m changing my app from VAADIN 6 to 7 and struggling with catching the detach events for idle sessions in V7.0.4 to clean some cache.

I followed the guidance in the BOV at https://vaadin.com/book/vaadin7/-/page/application.lifecycle.html
and the wiki at https://vaadin.com/wiki/-/wiki/Main/Cleaning+up+resources+in+an+UI

The web.xml configuration parameters ‘heartbeatInterval (20 secs)’ and closeIdleSessions (true) are set correct cause I can request them correctly
from within my UI.

  • I call my application in Firefox 20 and follow the heartbeats with the “HttpFox”- tracer add-on. Perfect !
  • I change the URL to ‘about:blank’ and the heartbeats vanish ! Perfect !
  • I wait 3 heatbeat intervalls and … nothing happens.

My code is basically a copy out of the WIKI- article:


...
public class SimpleiUI extends UI implements DetachListener{

    protected void init(VaadinRequest request) {
        ...
        addDetachListener(this);
        System.out.println("UI-IdleTimeout: " + getSession().getConfiguration().getHeartbeatInterval() + ",IdleClean:"+ getSession().getConfiguration().isCloseIdleSessions() );
       ...
    }
    public void detach(DetachEvent event) {
        System.out.println ("Detach listener");
    }
}

I’m lost, where is my misunderstanding ?

Thanks for any help !
Gerd