We just came across a serious limitation in Hibernate especially in a distributed programming environment such as GWT-RPC or SOA.

In our scenario Hibernate is not able to recognize collection objects once they travel over network (serialized). So, it ends up deleting all the previous entries in the database and recreates them again based on the collection passed in.

We currently convert PersistentSet into HashSet and serialize it for sending to GWT client. When the same set come back to server for persistence, Hibernate is not able to recognize the objects in the HashSet. So, it ends up deleting all the entries and recreating them again. This is not acceptable behavior thus forcing us to manage Collections using custom coding efforts.

It appears this is a limitation in how the collections are implemented in Hibernate because it assumes all the objects or collection objects reside in the same JVM for their entire life. Whatever happened to the distributed computing such as SOA/CORBA/GWT-RPC??

Any simple work-around or a clean solution would be highly appreciated.
MA

I'm going to go out on a limb here and say that you didn't override equals/hashcode? After serialization collections cannot tell the difference between objects if you haven't implemented the objects in this fashion.

Nice try! I checked for it. Unfortunately Hibernate is looking for the exact object reference with == operator.
please refer: http://www.hibernate.org/116.html#A15

Touche. I wonder if this has to do with not forcing versioning / version cascading in models.