My problem is, that I don't want the feature automatic update of changed objects. So I have to make the loaded objects transient.
But I also don't want to close the session because it's creation costs too much performance.
So is there a way to separate the objects from the session without closing it or to disable the automatic update for my objects somehow else?
Please let me know.

Actually creating SessionFactory is more expensive in terms of performance, whereas Session is lightweight and can be created easiely.

Well, you're right. I have done some measurements (each time there are 10000 objects loaded):

- first time(SessionFactory and Session are created): ~ 7s
- only Session created: ~ 3,3s
- Session created before: ~ 1,5s

The times are only slightly influenced by the database-cache.
So you see the Session creation also takes some time.

Maybe the difference is caused by the fact, that when the session is still open the objects must not be recreated.
establishing a JDBC connection takes only 50 to 100 ms.

I think that when the session is open the connection would also remain open. That is why changes in objects can be persisted as changes in object take place (after the object has been associated with a session).