Jersey is Sun's production quality reference implementation for JSR 311: JAX-RS: The Java API for RESTful Web Services. Jersey implements support for the annotations defined in JSR-311, making it easy for developers to build RESTful web services with Java and the Java JVM. Jersey also adds additional features not specified by the JSR.
The latest version of the JAX-RS API's can be viewed at https://jsr311.dev.java.net/nonav/javadoc/index.html
If you are developing with Enterprise Server v3, you can install the Jersey samples and documentation using the Update Tool. Instructions for using the Update Tool can be found in the section Java EE 6 Tutorial Component.