Jersey 1.0 is an open-source, production-ready reference implementation of JAX-RS, the Java API for RESTful Web Services (JSR-311). Jersey makes it easy to create RESTful web services in Java.
In an earlier Tech Tip, Implementing RESTful Web Services in Java, Paul Sandoz and I introduced RESTful Web Services, JAX-RS, and Jersey, and showed how to write RESTful web services in Java that conform to the JAX-RS specification. In this tip you will learn how to configure data in JSON (JavaScript Object Notation) using Jersey 1.0. JSON is a lightweight data-interchange format that is based on the object notation of the JavaScript language. Because of it's simple text format, JSON provides a good alternative to other data interchange formats such as XML and is particularly attractive as a data interchange format for RESTful web services.
In this tip you will build a Jersey-based web application that provides information about printer status. The application returns the information in JSON format. To build the application, you will use the Maven 2 software project management tool. For more information about Maven, see Welcome to Maven and Building Web Applications with Maven 2.
Hibernate Annotations is my preferred way to map my entity classes, since they don't require any external file (thus keeping mapping info in your Java files), is fully integrated with all Hibernate mapping capabilities and Hibernate documentation encourages us to use this kind of configuration because it's more efficient.
Annotation driven mapping in Hibernate uses the standard JPA API annotations and introduce some specific extensions to deal with some Hibernate features. You can find a full reference in the official documentation.