I'm currently using Hibernate2 in a distributed enironment that implements services via remote EJB calls. My concern is this....We have clients that will need to include the Hibernate jars in their class loaders since Hibernate "sneakily" replaces the java.util.* collections with it's own. Is there a way around this? Can Hibernate be configured to return java.util.* collections instead?

No

We use transport classes instead of publish hibernate classes to the client!
So we convert them to decouple the persistence layer and the view layer!
Take a look at http://www.openitnow.org/jbossrad/architecture/persistence_en.html

Gio

That's unfortunate...we really didn't want to have to get into a scenario where deep copies were forced...Which is what we would have to do to use transport classes. It's misleading to say that Hibernate supports POJO's.

You can always implement your own serialization algorithm and replace the proxies with something you like. Just don't use a "null" marker for the edges of the graph.

BTW, you will need hibernate2.jar, cglib2.jar, odmg.jar, commons-collections.jar and probably commons-logging.jar on the client. It's about 1 MB. We already have a JIRA issue for a "smaller" client-side library, but no one had time yet to look at it.