Seesion in Vaadin 6

hi please i want to use a session with Vaadin 6 for when the user authentificated the data of this user will be saved but i dont find an example (im beginner in Vaadin )
Sorry my english is not good (thanks you for any help )

Hi ala,
i use session in my project like this:
HttpSession session=((WebApplicationContext) application.getContext()).getHttpSession();
Sorry my english is not good too.

thank’s but how can i use it ?? in methode for authetiificated ?? or I must to create another class session ??