This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
In the REST architectural style, data and functionality are considered resources and are accessed using Uniform Resource Identifiers (URIs), typically links on the Web.
The resources are acted upon by using a set of simple, well-defined operations. The REST architectural style constrains an architecture to a client/server architecture and is designed to use a stateless communication protocol, typically HTTP.
Java EE 6 introduced new package to deal with RESTful webservices named JAX-RS.
Developing RESTful webservices by JAX-RS very simple with simple annotations like @PATH, @GET, @PUT, @POST, @DELETE, etc.
Refer Oracle's website and study JAX-RS tutorials, you will gain knowledge in RESTful webservices.