gwt - When is Widget OnUnload() is called? -

can please tell me when widget's onunload() called?

i tried override however, never been accessed. best way unload composite, using rootpanel.get("dev1").clear();

if want stop timer when leave page use closehandler. handler called while page closing , refreshing.

window.addclosehandler(new closehandler<window>() {      @override     public void onclose(closeevent<window> event) {         timer.cancel();     } }); 

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if want stop timer when clearing vertical panel use removefromparent.

this overridden method called when widget removed form parent.

private timer timer = null;  /*  * entry point method.  */ public void onmoduleload() {     final label label = new label("hello ") {         @override         public void removefromparent() {             if (timer != null && this.isattached()) {                 timer.cancel();                 system.out.println("timer stopped");             }             super.removefromparent();         }     };     timer = new timer() {          @override         public void run() {             label.settext("hello " + (int) (math.random() * 100));         }      };     timer.schedulerepeating(500);      final verticalpanel verticalpanel = new verticalpanel();     verticalpanel.add(label);      button button = new button("remove label");     button.addclickhandler(new clickhandler() {          @override         public void onclick(clickevent event) {             label.removefromparent();         }     });     verticalpanel.add(button);      rootpanel.get().add(verticalpanel); } 

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as per comments try below code clear method overridden verticalpanel.

    final verticalpanel verticalpanel = new verticalpanel(){         @override          public void clear(){             if(this.isattached()){                 timer.cancel();             }             super.clear();         }     };     verticalpanel.getelement().setid("div1");