I have been trying to figure out how to use JAX-RS for quite some time. I started from the very basic concepts and then to gradually understand the annotation styled programming, the meaning of @Path, @Get, @Post, etc.
To my understanding, as to what has been mentioned in a lot of places, JAX-RS is a framework that focuses on applying Java annotations to plain Java objects (Page 27, Bill Burke, RESTful Java).
I have then got confused beyond this point. If JAX-RS in itself is a framework that defines APIs dealing with annotations in order to implement RESTful web service, what's the meaning of "implementation of JAX-RS" such as "Jersey" and "JBoss Resteasy". Another layer on top of JAX-RS? Why do we need them?
Could someone provide me some insights about it? Many thanks!!!
JAX-RS is a specification for RESTful Web Services with Java. There is a reference implementation that is included in Java EE but since it is a specification, other frameworks can be written to implement the spec, and that includes Jersey, Resteasy, and others.