In a previous post on JCR I mentioned that JRS had consciously avoided the development of a client-side Java API. In fact there is no requirement for application clients to be developed in Java at all. One of the concerns we saw for previous Rational products was the complexity of the API and it's proprietary nature which made interoperability, integration and extension an expensive and complex proposition.
For Java client applications we really don't expect the use of the JDK and have tested with both Apache HttpClient and Abdera (for feed/entry creation and parsing). These seem to be the preferred libraries the application teams want to, and probably should, use.
So at least for us in JRS, if not for the rest of IBM, "J" stands for the Jazz Project and not Java.