Just exactly how much can you do with a Session? I'm a bit unclear on this from the documentation.

Can one Session cover just kind of query or update?
E.g SessionFactory is to Session as Connection is to Statement

I've tried to just obtain one Session in the past and use it for everything, but sooner or later I run into trouble from not flushing.

Hibernate version:
3.0

Different options -
One -
Use 1 session per business method that is exposed to the client.
So, for example, if the client wants to do saveOrder(), that uses one session.
If client wants to invoke updateUser(), that uses different session.
This assumes that there is a clear separation between where the client ends and server starts. This is closer to a ejb 3.0 usage pattern.

Two-
Is to use one session per thread on the server. The session is started when Get or Post on servlet is invoked. The session is closed just after the response is sent.

Which one you use depends on your situation