The Aggregate Entity pattern makes a case for using BMP: best option for flexibility and performance. (Commentary).

Entity beans have been much maligned lately, largely far their inability to scale and difficulty to develop and maintain. However, there remain some compelling reasons to consider using entity beans to persist data in a J2EE application. For example, survivability of entity beans, where state can be recovered following a hard crash, lends to increased reliability when the server is running.

The serialization of state to an alternate store allows entity beans to utilize limited resources more efficiently. That is, activating and passivating beans can allow a server to complete a transaction even when its headroom has been exceeded. A developer can mimic such facilities in session beans, but why reinvent the wheel? Of course, the most significant difference between entity beans and session beans is conceptual, not concrete. Whereas a single session bean instance serves only one client, an entity bean, by virtue of a primary key, serves many clients. Entity beans are more conducive to an architecture where the persistence layer …