Enterprise beans—the deployment descriptor

The rules governing an enterprise bean's lifecycle, transaction management, security, and persistence are defined in an associated XML document called a deployment descriptor. See Deploying enterprise beans—overview.

Re-usable components may be customizable through a set of external property values, so that they can be modified to suit the requirements of a particular application without changing the source code. An enterprise bean developer can provide (within the deployment descriptor) a set of environment properties to allow the application developer to customize the bean. For example, a property might be used to specify the location of a database or to specify a default national language. At run time, an environment object is created which contains the customized property values set during the application assembly process or the bean deployment process.