Hi,
So as to use a cache and not the cache of the session, we've implemented a delegated session class, which is called in place of the normal session, and do an evict on every object loaded from data base.
The problem is that an error occurs each time we want to flush the session, and for example when asking for a new connection.

any idea ?
Thanks in advance

Don't do this... Just use the session for the unit of work then discard it. Only ever need to evict in special situations.