Be aware that a newer GAME proposal has since been released. This release is targetted at the Gadfly Drosophila annotations which are GAME 1.001 documents. I make no claims that they will work for other input files although they can be readily extended to cover other GAME structures.
There are two base classes in this release. The first is the StAXFeatureHandler which is the base class for elements that intend to create new Feature objects. Then there is the StAXPropertyHandler class that is base class for element handlers that only extend properties of the existing feature. All classes should be subclassed from one of these.