The examples in this directory are a compliment to the O'Reilly "RESTful Java with JAX-RS" book. This book has a detailed explanation of REST and JAX-RS. The appendix of the book also walks through all the example code provided within this directory.
You can buy this book at:
http://oreilly.com/catalog/9780596158040/
The author, Bill Burke, is the founder of the RESTEasy project.