I am serializing objects via XML between JBoss server and .NET client.
Everything works just fine except for deletes from child collections.

The child objects are removed from collections on client side and are not members of the collection when the parent is serialized back to the server. I de-serialize the object and use saveOrUpate to save the changes to the database. I use cascade=all-delete-orphan on each child collection.

Inserts and updates of child objects work fine. Deletes to not work at all. I suspect that the problem is that when I de-serialize the objects I am using a simple HashSet for the child collections.

What are the rules for de-serializing an object and getting it reassocaited with the current Session? Specifically what Set implementation should I use for child collections to get the deletes to work properly.