Here's a question for Mick Knutson: Does your book focus on a particular application server, or does it cover several of them?
I know that different app servers have different ways to configure security, for example. It's hard to describe how to configure these things without getting into the specifics of different servers.
The book primarily focuses on Glassfish, both standalone and embedded. There were several issues getting security and some custom configuration with the embedded version though.
There are also several recipes using Tomcat 7 server.
Most of the recipe's can easily be ported to other applications servers, but for the sake of standards, Glassfish and Tomcat where the easiest reference implementations to focus on.