JSR311 : JAX-RS : Java API for RESTful Webservices

This JSR provides an API for providing support for RESTful(Representational State Transfer) Web Services in the Java Platform.

This JSR : Final Approval Ballot is done on 22-Sep-2008.

You can find the details of this API here

Not heard of REST ? read it here.

Goals of this API are

POJO-based : The API will provide a set of annotations and associated classes/interfaces that may be used with POJO's in order to expose them as Web resources. The specification will define object lifecycle and scope.
HTTP-centric : The specification will assume HTTP is the underlying network protocol and will provide a clear mapping between HTTP and URI elements and the corresponding API classes and annotations. The API will provide high level support for common HTTP usage patterns and will be sufficiently flexible to support a variety of HTTP applications including WebDAV and the Atom Publishing Protocol.
Format independence : The API will be applicable to a wide variety of HTTP entity body content types. It will provide the necessary pluggability to allow additional types to be added by an application in a standard manner.
Container independence : Artifacts using the API will be deployable in a variety of Web-tier containers. The specification will define how artifacts are deployed in a Servlet container and as a JAX-WS Provider.
Inclusion in Java EE : The specification will define the environment for a Web resource class hosted in a Java EE container and will specify how to use Java EE features and components within a Web resource class