Dan had an idea the other day to get CXF JAX-RS proxies enhanced a bit for them to support the asynchronous calls. After all, HTTP centric JAX-RS 2.0 and CXF WebClient clients support such calls with AsyncInvoker.
So here is what we have started from. Simply register InvocationCallback with a proxy request context as shown in the examples and make the asynchronous call. The proxy method will return immediately and the callback will be notified in due time once the typed response is available. As the examples show one can register a single callback or a collection of callbacks bound to specific response types.
I suppose we can consider generating typed asynchronous proxy methods from the service descriptions such as WADL going forward.
This feature will be available in CXF 3.1.7. Give a try please, refresh your JAX-RS proxy code a bit, enjoy.