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Hi,

I have two POJOs "A" and "B". Both are marked as "lazy" and A to B is a one to one relation. I have marked the association as outer_join=true so B is always fetched.

Now consider the following scenario, when ehcache is enabled

1)First time Load "A". B is also loaded, and B is not "CGLIB" enahanced class. Both A and B are put in the second level cache

2)Once again load "A" in different transaction. Now "A" is loaded from ehcache. But "B" is not loaded. "B" is shown as "CGLIB" enhanced object in the debugger.

I have following questions
1) why is "B" CGLIB enhanced object when it is loaded from cache and regular object when it is loaded from DB.
2) How does ehache works for assoicated object? Are associated objects also loaded?

I think it's a question of which logical layer the "fetch" plan relates to. As I understand it, "fetch" is mainly to tell Hibernate what SQL to generate when it goes to the database - not necessarily what plan to use when traversing the various caches.

So when neither A nor B are cached, and you're doing fetch=join, it will pull back both objects so there's no need to proxy/enhance B. However the second time you try, it finds A in the cache and so has to decide what to do about B. It sounds like although B is cached, Hibernate doesn't try and figure this out when it finds A - it will just wait until you try and access B before going off to look for it. (Presumably it will then find it in the 2nd level cache ok.) Maybe this is a result of your setting lazy to true ?(incidentally, if you want eager fetching why is lazy set to true ?)

As to why B is CGLib enhanced, is the association nullable ? There's a short section in the new Hibernate book (p.566) about lazy loading and one-one associations, where it says that unless "constrained=true" on the association, Hibernate can't know whether B is null or not without hitting the database, and so can't create a dymanic proxy. So to enable lazy loading - which is how you've configured it - it enhances the bytecode instead.

John