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Java EE Terminology

A number of concepts and terms have been introduced by Java EE. The following list defines these items:

• Application Server—An integrated set of software that provides several functions including a Web Server, JSP Server, JNDI Server, and an EJB Server.
• Application Assembly—The process of collecting the various parts of the Java EE application (Web pages, JSPs, EJBs, and so on) and placing them into WAR and/or EAR files for deployment onto an application server.
• Application Deployment—The process of distributing the various parts of the Java EE application (Web pages, JSPs, EJBs, and so on) to the appropriate servers within the application server.
• JAR File—Java Archive. A single compressed file that usually contains many files of different types. Compression saves disk space and network bandwidth.
• Deployment Descriptor—An XML file within a WAR, EJB-JAR, or EAR file that contains the description of the contents of the file. It is used by the application server deployment tool.
• WAR File—Web Archive. A specialized JAR file that contains the portion of the application that will be deployed to a Web Server. The WAR file includes a deployment descriptor, plus all the files (the Web pages, JSPs, Java Servlets, and so on) destined for the Web Server.
• EJB-JAR File—A specialized JAR file that contains the portion of the application that will be deployed to an EJB Server. The EJB-JAR file includes a deployment descriptor, plus all files needed to implement the EJB(s).
• EAR File—Enterprise Archive. A specialized JAR file that usually contains the entire Java EE application. It includes a deployment descriptor, as well as WAR and EJB-JAR files. The deployment descriptor describes the WAR and EJB-JAR files, plus any security and database information specific to the application.
• Resource Adapter—A system-wide driver used by Java EE applications to access resources, such as a database.
• Web Service—A software system designed to support interoperable machine-to-machine interaction over a network.