Hibernate version:
3.0.3

I'm using a table-per-class mapping strategy with some joined-subclasses, and I'd like to be able to convert an object into a subclass. I have an item persisted in my system as a generic type, and it is later converted into something more specific when a user reviews it and decides what it should be.

I've tried a couple things that haven't worked, like making a new subclass instance and copying the existing data in (including the id), but that didn't work, unsurprisingly. My only real idea at this point is to manually add a new entry to the subclass table and re-fetch, but that seems like a brittle solution.

I've searched these forums and found several other questions like this, but they were either unanswered or inapplicable. I can't be the only one trying to do this, so I'd appreciate any help.

Is this just not possible with Hibernate? Judging from the lack of replies, maybe that's the case. If so, this could be a good feature to add.

I'm working on this problem as well. If you insert the superclass's ID into the subclass table manually, a call to session.get(Subclass.class, ID) will return your Subclass instance. However, I am looking for a more hibernate specific way of accomplishing this, since I haven't found a way to get the JDBC Connection from the Hibernate Session to perform the manual insert yet.