It's JBossCache 1.4.0SP1. Your restatement is correct, Brian, more specifically: 1. We put aspectized Participant object in the cache 2. We add Message object to the Participant.newMessages List 3. Message object has reference sender to Participant object and reference recipient to Recipient object which class is an abstract super class of Participant object class. 4. Recipient class declared with @InstanceOfPojoCacheable 5. So, both, sender and recipient are aspectized but are not in the cache 6. recipient in this case is a Conference object which has List of its Participants 7. In turn, Participant has a List of Conferences it participates in. 8. Actually, all these POJOs are [derived from] ValueObjects with a HashMap of attributes. We debugged the deadlock again and found out that during serialization of the first sender's Conference attributes the framework (RegularObjectPersister.writeSlotWithFields()) tries to serialize MarshalledClassProxy which substitutes? attributes. And here the whole story begins.... MarshalledClassProxy.advisor gets serialized and this leads to whole cache serialization. Hope this explanation helps :) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3982609#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...