This week's book giveaway is in the OCAJP forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide 1Z0-808 and have Jeanne Boyarsky & Scott Selikoff on-line! See this thread for details.
Not sure what this has to do with Object Relational Mapping technologies. Anyway, I think you might be asking a question about some of the core Java API (please correct me if I'm wrong and this really is an ORM question), in which case you might want to read this. I'm moving this to a more appropriate forum.