The user will not be challenged as long as they access only unprotected resources in any of the web applications on the virtual host.
Upon access to a protected resource in any web app, the user will be challenged to authenticate, using the log in method defined for the web app.
Once authenticated, the roles associated with this user will be utilized for access control decisions across all of the associated web applications, without challenging the user to authenticate themselves to each application individually.
If the web application invalidates a session (by invoking the
javax.servlet.http.HttpSession.invalidate() method), the user's sessions in all web applications will be invalidated.
A session timeout does not invalidate the SSO if other sessions are still valid.