When Hibernate notices that a session has been closed when lazy loading, why can't it just get a new one? That would save me a massive amount of hassle.

The domain object might have been transported to an environment that is not hibernate aware, eg, Swing Client over CORBA, so it could not possibly work. There are quite a few approaches to manage this, eg, Web environment commonly uses a Filter to open and close the environment. Alternatively, you could always load what is required, sure you need to be more aware of whats going on after the domain object(s) become transient - which in my mind is a good thing.

Yea, I have been using the one-session-per-request pattern, and that works great for model-2 frameworks, but I'm wondering how well that will transfer to a component based system where state is often maintained across requests.

I am a heavy user of Tapestry and Hibernate through a EJB SLSB layer using a command pattern architecture. In this senario you are required to load what you need for the rendering process. Mostly this occurs in a single network fetch. Other options such as a wizard like operation, the detched session can work or using Transient object which are re-associated with the session (this I apply alot). Chapter 8 HIA has good coverage of the options.

I'll take another look at that chapter. Thank you.