from bryan Kearney:

The pre processor throws an exception in the preProcess method whose class is candlepin.UnauthorizedException which inherits from candlepin.CandlepinException which inherits from lang.RuntimeException.

Our exception mapper implements ExceptionMapper<RuntimeException> (lang.RuntimeException).

Under 2.0 Beta 4, the mapper is called with an instance of candlepin.UnauthorizedException as I would expect. In the GA, the mapper is not called.

– bk