The J2EE specification provides a means for J2EE application components to refer to administered objects that are associated with a resource. The reference is done by using "logical" names called resource environment references. You can use the deployment descriptor editors to define resource environment references.
At deployment, the resource environment references are bound to the actual administered objects in the target operational environment.
For each resource environment reference that you define, a resourece-env-ref element is added to the deployment descriptor for that application component. Resource environment references are scoped to the application component where they are defined, so they are not accessible to other application components during run time. Other components can define resource environment references with the same name without causing a name conflict.
Resource environment references are available only for J2EE 1.3 or later, and EJB 2.x.
To define a resource environment reference: