Closed
Description
SessionRegistryImpl can be used to track sessions. We can register new sessions with it. When the session expires it'll be automatically removed, because it implements ApplicationListener.
However, as of Servlet spec 3.1 it is possible to change the id of the current session without invalidating it by calling Session.changeSessionId(). But, SessionRegistryImpl will not be aware of the change and continues to have the older session id. The older session id will never be removed.