The goal of a framework is to provide a reusable and extendable set of classes and interfaces that will serve as a foundation on which you can construct your own applications more efficiently. The Restlet project was started from the observation that no Java framework was available to help developers build RESTful applications.
Watch this tutorial on http://www.restlet.org/documentation/1.1/screencast/

Today writing portable Web applications that can use the power of the Comet technique is almost impossible: Tomcat, Jetty, and Grizzly/GlassFish application server all have their own set of private APIs. Atmosphere leverages and builds on Project Jersey and the Java API for RESTful Web Services (JAX-RS). Jersey is the open resource reference implementation of JAX-RS that makes it easier to build RESTful Web services. Atmosphere and Jersey complement each other, with the goal of making it easier to build Comet-based Web applications that include a mix of Comet and …

After an extended milestone phase, Spring 3.0 finally went GA (generally available) in December 2009. The third generation of the framework provides comprehensive annotation-based configuration, unified expression language support, REST-enabled web MVC, and support for Java EE 6. This talk discusses Spring as a modern annotation-oriented application framework, covering the component model trends as well as selected Spring 3.0 feature highlights.

The Play framework is a clean alternative to bloated Enterprise Java stacks. It focuses on developers productivity and targets RESTful architectures. Play is a perfect companion for agile software development.

Arjen addresses Spring 3.0 support for REST in Spring MVC including, URI templates, content-negotiation, and other RESTFul concepts. Starting with an overview of REST, he then addresses the new RESTful features in Spring, including: RESTful URI’s, URI templates, Content negotiation, HTTP method conversion, and ETag support.
http://www.infoq.com/presentations/rest-web-application-architectures

Restlet is a lightweight REST framework. These screencasts will take you through the installation of Restlet in an Eclipse IDE and the creation of a simple Restlet application.
http://www.restlet.org/documentation/1.1/screencast/

Many people claim their Web APIs and enterprise applications offer a “RESTful” interface. But merely getting by without a SOAP envelope, or tunneling all kinds of information through URIs, doesn’t magically sprinkle REST pixie dust on bad designs. This session will start with an extra-fast intro to REST before listing the most common patterns and anti-patterns of applying REST design principles, covering issues such as the (un)importance of URI design, resources vs. representations, and the role of hypermedia.