Currently, my app does not use entity beans at all (only regular data objects and DAOs) and it runs in a single JBoss. Pretty soon, it will have to run in a cluster. I reckon that there might be a problem with synchronizing access to object instances in the DB that entity beans could help me with. Is there any other reason to use entity beans? I've heard negative stuff about CMP, in particular, the performance. Can anyone give me an advice or at least point me to discussions and/or books that delve into this subject (of choosing the right persistence technique).