I have a wizard-type screen flow and am thinking of using the Long session with automatic versioning pattern. I expect to have a fair number of abandoned sessions and I want to know what the consequences of this are. Will hibernate automatically expire the disconnected sessions? Can I just stick them in httpsessions and let the container expire them? Would the disconnected sessions consume a lot of system resources (assuming they've got a cache of objects in them)?

Any tips appreciated.

It would be best to disconnect() the session and place it into session scope between the requests. Then during the subsequent requests, you can simply reconnect() the session.

This serves two purposes. One, because of the disconnect, the underlying jdbc connection can be released for better resource management by the server. Secondly the hibernate session would be destroyed on session timeout by it being in session scope.

HTH