Each J2EE application and its module consist of deployment descriptor. Since the deployment descriptor is declarative it can be changed without any change in the source code.
The web application deployment descriptor file does pretty much what it's name says it does: it describes how the web application should be deployed.For web applications written using the Java programming language, the web application deployment descriptor is written using the EXtensible Markup Language (XML) syntax.
A deployment descriptor (DD) refers to a configuration file for an artifact that is deployed to some container/engine. In the Java Platform, Enterprise Edition, a deployment descriptor describes how a component, module or application (such as a web application or enterprise application) should be deployed.
For web applications, the deployment descriptor must be called web.xml and must reside in the WEB-INF directory in the web application root. For Java EE applications, the deployment descriptor must be named application.xml and must be placed directly in the META-INF directory at the top level of the application .ear file.
For Java EE applications, the deployment descriptor must be named application.xml and must be placed directly in the META-INF directory at the top level of the application .ear file.
The web application implementation descriptor computer file does basically what it's name says it does: it explains how the web program should be implemented.For web programs published using the Coffee development terminology, the web program implementation descriptor is published using the EXtensible Markup Language (XML) format.
A deployment descriptor (DD) represents a configuration file for an artifact that is implemented to some container/engine. In the Java Platform, Enterprise Version, a implementation descriptor explains how an element, component or application.
- A deployment descriptor is a configuration file for a web application or EJB application which is to be deployed to web or EJB container.
- The deployment descriptor should contain standard structural information for all enterprise beans in an EJB application.
- The file name is EJB-jar.xml, the descriptor of EJB informs the EJB server about the classes that make up the implementation of bean, both home and remote interfaces.
- A standard deployment descriptor should contain structural information for each enterprise bean.