Vaadin 7.2 and later offers this static method:
VaadinSession.getAllSessons( javax.servlet.http.HttpSession httpSession )
The doc says:
Retrieves all VaadinSessions which are stored in the given HTTP session
How does a user ever have more than one VaadinSession
per HttpSession
? Does that happen by an action performed by the user, or by me programmatically in my Vaadin app?