How to invalidate session in JSF 2.0?

What is the best possible way to invalidate session within a JSF 2.0 application? I know JSF itself does not handle session. So far I could find

private void reset() {
    HttpSession session = (HttpSession) FacesContext.getCurrentInstance()
            .getExternalContext().getSession(false);
    session.invalidate();
}

1. Is this method correct? Is there a way without touching the ServletAPI?
2. Consider a scenario wherein a @SessionScoped UserBean handles the login-logout of a user. I have this method in the same bean. Now when I call the reset() method after I'm done with necessary DB updates, what will happen to my current session scoped bean? since even the bean itself is stored in HttpSession?