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Disable browser back button and use or interceptor
So please let me know how to disable browser back button. OR if user uses back button, the session is lost and he has to login again.
And how to use interceptor for user action tracking. Means to track user action from one page to another. I tried to use interceptor but in vain.
Well by default a Vaadin application is just one page. So pressing back button doesn't do anything else than navigate away from the application. Are you sure you want to disable user's possibility to navigate away from the application? If you want the session to be invalidated, when user navigates away either by typing a url, pressing back button (or forward button) or clicking an outside link from your application, that is another question and unfortunately can't answer that. There is a CloseListener, that you can listen from main window, but unfortunately that is also called when user refreshes page so that doesn't really help you.
Vaadin application doesn't consist of pages, but instead just one page where you replace contents of the main window. You could track user action however you like in your logic, that switches your views.