Bridge methods for covariant return types cannot be invoked on client proxies

For a method override using covariant return types, the Java compiler generates a bridge method that has the same name and parameter types as the real one. If a resource class has such an override, and inherits JAX-RS annotations from an interface it implements, the two methods will correspond to the same annotated method.

Because of this, as implemented in CXF-7670, the real method is mapped to the operation defined by the annotations, while the bridge method is ignored. This causes a javax.ws.rs.ProcessingException when trying to invoke it on client proxies built from the concrete class. This kind of invocation happens when the proxy is upcast.

I already have a fix for this on top of CXF 3.3.8. The pull request is in progress.