Sams Teach Yourself J2EE™ in 21 Days

Day 8. Transactions and Persistence

You have spent the last three days covering EJBs in detail. In particular, you learned how to specify, implement, configure and deploy container-managed persistence (CMP) Entity beans. Along with BMP Entity beans (Day 6, “Entity EJBs”) and Session beans (Day 5, “Session EJBs”), you now have a good appreciation of the EJB technology.

EJBs have been called transactional middle-tier components. Until now, you haven't had to worry too much about transactions in an EJB context because they are reasonably transparent. In fact, you have been using container-managed transaction demarcation. However, for those cases where you require explicit control, EJB provides two solutions. You can write beans that manage their ...