404 error with Navigation Example

Hi,
I am a beginner with VAADIN and just met a problem which I could not solve.
Just downloaded the source code of this example in connection with navigation:


http://demo.vaadin.com/book-examples-vaadin7/book/#advanced.navigator.basic

But after building and running the application on GlassFish Server 4, I am getting a 404 error page.

Any advice is appreciated.

Bah, I forgot the WebServlet annotation… Case is closed. :confused: