Java Platform, Enterprise Edition: The Java EE Tutorial. Oracle - web version
The Java EE Tutorial. Oracle - pdf
This is a RESTful application web service that uses JAXB (XML annotations for Java API for XML binding (JAXB) serialization to perform CRUD (create, read, update, delete) operations for a entitys.
After deploy project on your aplication server, open in browser the web client URL:
http://localhost:8080/customer/
You can see all customer entities already created on page:
http://localhost:8080/customer/webapi/Customer/all, format XML or JSON