Identify four valid requests in a RESTful service using JAX-RS.

The following principles encourage RESTful applications to be simple, lightweight, and fast:
* Resource identification through URI
* Uniform interface: Resources are manipulated using a fixed set of four create, read, update, delete operations: PUT, GET, POST, and DELETE. PUT creates a new resource, which can be then deleted by using DELETE. GET retrieves the current state of a resource in some representation. POST transfers a new state onto a resource. See Responding to HTTP Methods and Requests for more information.
* Self-descriptive messages
* Stateful interactions through hyperlinks
Reference: The Java EE 6 Tutorial, What Are RESTful Web Services?