Binod has written a blog entry entitled "Lazy Initialization of Application Server Services" to present a sort of FAQ on Sun's use of lazy initialization in Glassfish.
Most of the developers are not going to use all the services in the Application Server. I am not talking about those who develop really complex EE applications all the time, but about developers who download the Application Server and just try out a few samples, or folks who learn one or two technologies at a time or even folks who work on small projects that use only some of the technologies from the Java EE stack. This group of developers would not like to incur the overhead of startup-time/memory for all the services they would not use.

Hence now, the Sun Java System Application Server does not start all the containers during startup. In fact when you install Application Server and start it afresh, there will be only a handful essential services initialized, namely a local JNDI provider, JMX connector (for administration).