Day 1. Understanding EJB Architecture

Developing enterprise applications has become a daunting task. Enterprise applications are complex, used by many users, developed by multiple teams, and deployed on heterogeneous systems that might span multiple environments. In addition, enterprise applications have to be distributed, secure, transactional, reliable, scalable, flexible, expandable, reusable, and manageable. Moreover, enterprise applications must be integrated with existing systems, and leveraged against the existing infrastructure.

Enterprise JavaBeans (EJB) is a component-based architecture for developing, deploying, and managing reliable enterprise applications in production environments. EJB architecture is at the heart of the Java 2 platform, Enterprise Edition (J2EE). With the growth of the Web and the Internet, more and more enterprise applications are now Web based, including both intranet and extranet applications. Together, the J2EE and EJB architectures provide superior support for Web-based enterprise applications.

The following is a summary of today's target in exploring both the EJB technology and J2EE architecture. You'll learn

• What EJB is, and its benefits in simplifying the writing of enterprise applications

• How EJB is different from ordinary JavaBeans

• About the big picture of the J2EE, and where EJB fits into it

• What flavors of beans are available, and the characteristics of each

• The importance of the EJB container, and the available common services provided to your beans

• More about the roles and responsibilities in developing and deploying J2EE applications—who does what