Chapter 14. Migrating to EJB 3
This chapter covers
- Migrating session beans and MDBs
- Migrating CMP entity beans
- Migrating JDBC DAO and O/R frameworks
In today’s IT world, migration has become an integral part of the application development lifecycle. Software products and technology change every few years, requiring the migration of applications from one platform (or one version) to another. From a budget standpoint, migration is certainly less expensive than rebuilding applications, and thus easier to justify to management. IT shops normally migrate their applications to increase their longevity and improve maintainability. Countless applications have been written using EJB 2 and many of these applications will be migrated to use EJB 3. Many customers who have built their persistence tier using JDBC, JDO, or O/R frameworks like Hibernate or TopLink will be migrating to the EJB 3 JPA, since it is the new industry-standard persistence API for the Java platform. Some companies may only be able to justify migrating a portion of their applications to EJB 3, leaving others living in an EJB 2 world. This will introduce a new wave of interoperability issues.