Felix is a community effort to implement the OSGi R4 Service Platform, which includes the OSGi framework and standard services, as well as providing and supporting other interesting OSGi-related technologies. The ultimate goal is to provide a completely compliant implementation of the OSGi framework and standard services and to support a community around this technology. Felix currently implements a large portion of the OSGi release 4 specification, but additional work is necessary for full compliance. Despite this fact, the OSGi framework functionality provided by Felix is very stable.
Apache CXF is an open source services framework. CXF helps you build and develop services using frontend programming APIs, like JAX-WS. These services can speak a variety of protocols such as SOAP, XML/HTTP, RESTful HTTP, or CORBA and work over a variety of transports such as HTTP, JMS or JBI.