There's an ongoing effort in Roller to migrate from Hibernate to JDO. Mostly, this is due to Apache's silly rule about no L/GPL dependencies - even if they're downloaded separately. I think this is a valiant effort, especially if JDO performs as well as Hibernate.
However, it was interesting to see the following message on the mailing list this morning:
i have experience using jdo, and jpox in particular, with a commercial
product. first, you probably already know this, but jdo is dead (from a
spec perspective anyway). it will be phased out in favor of ejb3
persistence. maybe that transition will be graceful, maybe not. i see
jpox has ejb3 on their roadmap, but not sure what that means.
second, jpox has really, very atrocious performance issues. the jpox folks admit that performance is a low priority, as they are an ri. if someone wants the details on this, i can dig them up.
Interestingly enough, this message is from a Sun employee. It's interesting to hear someone from Sun say that "jdo is dead". What are you thoughts? Should Roller change their persistence backend just to satisfy Apache?
Of course, now you'll tell me your favorite Apache-licensed persistence framework and why it's worked so well for you. The real question is - are you willing to re-write Roller's backend using it?