The author, Jose Sandoval, goes over the same application for the different frameworks: JAX-RS, Restlet, RESTEasy, and Struts2. Well, the RESTEasy part is quickly skipped as RESTEasy builds on top of JAX-RS.
I tend to disagree with the way the example code is written, but that could just be down to a difference of opinions or different cultures. It’s important to look at the downloadable example code as the book was written prior to Restlet 2.0 release. The example code covers both versions.
The book has sufficiently many typos and minor flaws that it becomes annoying.