What’s new in the EJB 2.0 specification?

What’s new in the EJB 2.0 specification?

- The following are the differences specified by Sun in EJB 2.0.

- Local interfaces, which improve the efficiency of intra-container entity relationships - to access lightweight entities only within the EJB container.

- The remote access overhead associated with remote interface can be avoided with local interfaces, so that the tightly coupled beans can communicate more efficiently.

- Container-managed relationships, in which the container manages object relationships between entity beans –In the earlier versions entity beans relationships are being managed manually, which is a burden for the EJB developers.

- In EJB 2.0 the entity bean itself can manage the relationships which are based on integrity model.

- Changes to EJB QL, a query language for portable EJB finder methods – It is a container-persistence model.

- It provides the navigation facility through networks of entity beans connected by container-managed relationships.

- It is made mandatory to use the SELECT clause in EJB QL queries.

- Duplicate result set can now be eliminated using DISTINCT in SELECT clause.

- Objects can also be selected using an OBJECT operator in the SELECT clause.

- The presence or absence of a value in a collection is a choice that is provided by MEMBER OF operator to search.

What’s new in the EJB 2.0 specification?

Asynchronous Messaging :

- It allows the development of loosely-connected systems.

- These systems are typically more resilient in the event of failures, and more easily extensible as new applications are developed.

The integration of JMS and EJB :

- It allows enterprise beans to participate fully in loosely connected systems.

- Through this integration, message-driven beans can receive and act upon JMS messages, without the involvement (or existence) of an application client user interface.

Local interfaces :

- They improve the efficiency of intra-container entity relationships.

Container-managed relationships :

- In these, the container manages object relationships between entity beans.

Changes to EJB QL :

- A query language for portable EJB finder methods.

- Enhancements to the interfaces of Message-Driven Beans (MDBs), as well as to the home interfaces of remote entity beans.

Inter-Server Interoperability :

- It enables heterogeneous environments.