Having just finished a project where we rolled our own RESTful web services I was keen to investigate how the frameworks had moved on since we made our decision.
So after some investigation I decided to try out Apache CXF (we'd used XFire on a different project to provide JAX-WS web services and so I wanted to the direction its going in now that Celtix has been combined with XFire to produce CXF); and of course CXF has support for the JAX-RS specification.
So far I've only managed some preliminary investigations but I must say that it's looking very good and I'm champing at the bit to try it on a commercial project.
One of the main advantages of SOAP based web services is WSDL, with tools such as Axis2 and XFire it's straightforward to automatically generate clients. However that's not been the case with plain old XML over HTTP web services.
So I was very happy when I came across WADL (Web Application Description Language). It does for web applications what WSDL does for SOAP based web services. Again I've only done some simple proof of concept work so far but it looks very good.
I've always found that SOAP web services and WSDL were, well, over complex for the vast majority of applications, and SOAP adds a lot of overhead to simple messages. However, it's been the only real standard for web services and for defining an api for web applications for a while now.
With the introduction of JAX-RS combined with WADL, and a framework like Apache CXF though, I see a new renaissance in the spread of well documented simple to use and understand web services. I'm looking forward to expanding my proof of concept work into a real commercial project.