J2EE™ Tutorial, The

The Message-Driven Bean Class

The code for the SimpleMessageEJB class illustrates the requirements of a message-driven bean class:

• It implements the MessageDrivenBean and MessageListener interfaces.

• The class is defined as public.

• The class cannot be defined as abstract or final.

• It implements one onMessage method.

• It implements one ejbCreate method and one ejbRemove method.

• It contains a public constructor with no arguments.

• It must not define the finalize method.

Unlike session and entity beans, message-driven beans do not have the remote or local interfaces that define client access. Client components do not locate message-driven beans and invoke methods on them. Although message-driven beans do not have business methods, they may contain helper ...