I was messing around with JAX-RS and made an application which calls REST services which produce JSON. I tried Jersey and everything went fine, but I had to switch to RESTEa
Solution: add the following in your web.xml
resteasy.servlet.mapping.prefix /rest
Where /rest is the beginning of your /rest/*
/rest/*
(Source: http://docs.jboss.org/resteasy/docs/2.0.0.GA/userguide/html/Installation_Configuration.html#d0e72)