Deployment Descriptors

Deployment descriptors describe the contents of deployment units and configure components and applications to their environment. They also externalize the relationships between components, so those relationships can be managed without writing or changing program code. Deployment tools usually automatically generate deployment descriptors, so you do not have to edit and manage them directly.

There are five types of deployment descriptors, each of which corresponds to a type of deployment unit:

 

EJB deployment descriptors are defined in the Enterprise JavaBeans specification.




Web deployment descriptors are defined in the Java Servlet specification.




Application and application client deployment descriptors are both defined in the J2EE platform specification.




Resource adapter deployment descriptors for Java Connectors are defined by the J2EE Connector architecture specification.

Each deployment descriptor type is defined in its corresponding specification as an XML Document Type Definition (DTD).

Deployment descriptors contain information used by a component's container and also contain information that the component can access directly by way of the JNDI. The JNDI is a standard interface to an enterprise object name service.

 

Source: Sun Microsystems