Enterprise JavaBeans™ is the core component technology of the Java Enterprise Edition platform. It is an enterprise infrastructure designed to provide developers with the automatic management of many of the services essential to enterprise applications. The EJB containerthe immediate environment of enterprise bean components and the provider of managed services to themis at the center of this architecture.
However, to use this managed environment in earlier versions of EJB, developers had to write to APIs that focused more on the EJB container’s requirements than on the business logic of enterprise applications. Consequently, EJB development was unnecessarily complex. For example:
Implementation of various EJB interfaces led to a lot of boilerplate code for methods that were required by the interface, but not needed by the application.
An XML deployment descriptor was required to integrate the application with its environment and with container services. Access to the components’ environment was clumsy and nonintuitive.
The design of container-managed persistence made domain object modeling unnecessarily complex and heavyweight. While container-managed persistence was originally conceived as an ease-of-use facility, in practice, it was awkward and limiting.
Workbook de la 3ra edicion: