EJB

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EJB

EJB

(Enterprise JavaBeans) A software component in the Java EE platform, which provides a pure Java environment for developing and running distributed applications. EJBs are written as software modules that contain the business logic of the application. They reside in and are executed in a runtime engine called an "EJB Container," which provides a host of common interfaces and services to the EJB, including security and transaction support. At the wire level, EJBs look like CORBA components.

Three Types of EGBs
The three types of EJBs are: (1) session beans perform processing, (2) entity beans represent data, which can be a row or a table in a database, and (3) message driven beans are generated to process Java Messaging Service (JMS) messages.

Very Versatile
EJBs inherently provide future scalability and also allow multiple user interfaces to be used. For example, both a Web browser and a Java application could be used to access EJBs, or one could be switched for the other at a later date. However, if these are not important issues, servlets, JSPs and regular Java applications can be used for business logic rather than EJBs. See Java EE, EJB container, EJB local interface, JavaBeans, distributed objects and component software.
References in periodicals archive ?
Coverage includes (for example) session beans, entities, persistence features, message-driven beans, and Web services.
If you need EJBS, but message-driven beans are beyond the scope of your application, don't worry about it.
Blaze Advisor supports Web Services, Enterprise Java Beans (EJB) and Message-Driven Beans (MDB) in Java 2 Enterprise Edition (J2EE) platforms, Microsoft .
After walking through JBoss application server installation, the authors discuss JavaServer Faces for dynamic user interfaces, servlet technology for dynamic web applications, JDBC for connecting to databases, entity beans, and message-driven beans.
This edition of the workbook has been updated to include the latest features and covers the EJB 3,0 standard, including basic notions about server-side components, asynchronous messaging and web services, an architectural overview, resource management and primary services, entity and session beans, EntityManager (in Persistence), mapping persistent objects and entity relationships, entity inheritance, queries and EJB QL, entity callbacks and listeners, message-driven beans, timer service, the INDI ENC and injection, interceptors, transactions, security, and Java EE.
It covers the J2EE specification, the Eclipse plug-in paradigm, the Eclipse WTP project, JST, web standard tools, Eclipse web tools installation, J2EE standard tools projects, session and entity beans, message-driven beans, enterprise Java bean packaging and deployment, JavaServer pages, servlets, web packaging and deployment, web services and relational databases.
He covers Enterprise JavaBeans (EJB), session beans, entity beans, message-driven beans, and EJB services, basing the discussion on the EJB 2.
Even though the majority of Chinese developers still use older languages such as C++ and Delphi, almost 60% are using Java and a similar number expect to use message-driven beans from the EJB 2.
Specifically, the new version of Total-e-Server supports message-driven beans, enabling e-business solutions to accelerate B2B and other application-to-application communications.