I don't really understand the problem here.
The JSPs will always get the current data from the User object in the session. It doesn't cache this data. What do you mean, when you say you want to refresh User object.
Is your servlet(which updates the User object) not being called every time the user data is updated?
The problem i have is if a user's account is updated, i would like this user's bean to be refreshed.
Any object is session is latest one. What do you mean by refreshing?
How do i access each User object for each user in all sessions so that i can invalidate the ones i want?
If you want to share data across sessions, you either need to put it in ServletContext or you have to put it in some external resource like database.