RESTEasy

It can run in any Servlet container.

While JAX-RS is only a server-side specification, RESTEasy has innovated to bring JAX-RS to the client through the RESTEasy JAX-RS Client Framework.

This client-side framework allows to map outgoing HTTP requests to remote servers using JAX-RS annotations and interface proxies.

Features:

• Fully certified JAX-RS implementation
• Portable to any app-server/Tomcat that runs on JDK 5 or higher
• Embeddedable server implementation for junit testing
• Client framework that leverages JAX-RS annotations so that you can write HTTP clients easily (JAX-RS only defines server bindings)
• Client "Browser" cache. Supports HTTP 1.1 caching semantics including cache revalidation
• Server in-memory cache. Local response cache. Automatically handles ETag generation and cache revalidation
• Rich set of providers for: XML, JSON, YAML, Fastinfoset, Multipart, XOP, Atom, etc.
• JAXB marshalling into XML, JSON, Jackson, Fastinfoset, and Atom as well as wrappers for maps, arrays, lists, and sets of JAXB Objects.
• GZIP content-encoding. Automatic GZIP compression/decompression suppport in client and server frameworks
• Asynchronous HTTP (Comet) abstractions for JBoss Web, Tomcat 6, and Servlet 3.0
• Asynchronous Job Service.
• Rich interceptor model.
• EJB, Seam, Guice, Spring, and Spring MVC integration.