I am working with a number of different parent/child tables which I have successfully mapped as sets in hibernate. My application works beautifully except that Session.get creates zero-element sets when there are no rows in the child tables. Unfortunately, my application requires that in such circumstances the collections be set to null instead. How can I accomplish this?

I apologize in advance if this is documented somewhere, but I have reviewed the documentation and several other books and can find no answer to this question.

Thanks in advance.

Hibernate needs the collection reference in order to track additions to the collection. If your application requires empty collections to be presented as null, your best bet would be to configure the mapping such that Hibernate directly accesses the fields; then your applications can access through the property getter which does:


You can also modify the setter to "swap" the empty collection with null, but that will cause Hibernate to attempt to delete the collection during flush. I'd, obviously, not recommend this approach ;)

Thanks for the suggestion, Steve. I think the real solution, though, is to re-factor my domain code to use zero-length collections instead of nulls. Oh well. It was shaping up to be a pretty boring week otherwise. ;-)