Enterprise JavaBeans

15 June 2007

Enterprise JavaBeans (EJB) are key elements in J2EE (Java 2 Enterprise Edition) platform. They represent a server-side component technology, with focus on business logic shaping and object distribution. Enterprise JavaBeans are not a product, but they are a public specification which determines the rules to create business objects in special servers (EJB container in application servers).

Applications build using architecture based on EJB are inherently distributed and transactional, allowing huge scalability and safeness. For example, a business component being executed on a server requests transparently the services provided by other component being executed in other server. Enterprise JavaBeans can start transactions in a given resource (for example, a database) and those transactions are diffused locally or remotely.

EJB emphasizes reusing of business object through an development architecture where software engineers perform many distinctive and complementary tasks:

Enterprise Bean Provider (business specialist).
Application Assembler (application constructor).
Deployer (the one responsible to adapt application to business local conditions).
EJB Server Provider (middleware specialist).
EJB Container Provider (programmer).
System administrator.

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