Application Server can be purchased by itself or as a component of Java ES, a software infrastructure that supports enterprise applications distributed across a network or Internet environment. If you purchased Application Server as a component of Java ES, you should be familiar with the system documentation at http://docs.sun.com/coll/1286.2. The URL for all documentation about Java ES and its components is http://docs.sun.com/prod/entsys.5.
For other Sun Java System server documentation, go to the following:
Message Queue documentation
Directory Server documentation
Web Server documentation
Additionally, the following resources might be useful: