The examples in this directory are a compliment to the O'Reilly "RESTful Java with JAX-RS 2.0" 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 download all these examples at:
https://github.com/resteasy/Resteasy/tree/master/jaxrs/examples/oreilly-jaxrs-2.0-workbook
The author, Bill Burke, is the founder of the RESTEasy project.