This is a way noob question, but... I couldn't figure it out from the manual...

I have a <class ... lazy="true">. What exactly are the semantics of this? I gather that it causes something(s) to happen lazily, i.e. demand-driven (but by what, exactly?), which otherwise would happen eagerly, i.e. at load() time, but that's as far as my understanding goes.

Does the whole object get reconstituted at once, say, when an accessor is first called for any of its properties? Or is a separate SQL query made for each property if and when that property's accessor is called?

When is it safe to close() the session in which a lazy object was loaded?

Thanks,
~ mark

The whole object gets loaded at once as soon as it is first accessed. You can close the session after it is loaded, or anytime if you don't plan to access the object anymore.

Thanks for the quick reply, Michael:
:-)
~ mark

but you must remember that you need to keep session open until it is completely loaded. You load the object lazily but u need the transfer the session from classes to classes until you load the complete object.
As In the object oriented world, we have the good chance not to do everything in one class. "Create session, execute query, load object, load lazily loaded part and close the session". Here where is the advance of the lazy loading.?

I mean,In my opinion, if u load lazily not so much data, dont load it lazily or else you must handle the session management and concurency chaos for many accesses at the same time.
That breaks the complete efficient use of lazy loading.

I believe hibernate could and should handle the session management behind the codes. (At least for lazy loading-:)) Then I call it complete efficient great lazy loading.