The error occurs because the object’s ID is set. Hibernate distinguishes between transient and detached objects and persist works only with transient objects. If persist concludes the object is detached (which it will because the ID is set), it will return the “detached object passed to persist” error. You can find more details here and … Read more
Spring was developed as an alternative to EJB right from its inception, so the answer is of course you can use Spring in place of EJBs. If there’s an “advantage” to using EJBs, I’d say that it would depend on the skills of your team. If you have no Spring expertise, and lots of EJB … Read more
DAO is an abstraction of data persistence. Repository is an abstraction of a collection of objects. DAO would be considered closer to the database, often table-centric. Repository would be considered closer to the Domain, dealing only in Aggregate Roots. Repository could be implemented using DAO‘s, but you wouldn’t do the opposite. Also, a Repository is … Read more