The initialization algorithm create all Renderer instances at startup time. The side effect is a lot of classes are loaded into permgen memory without need.
With a clever trick we can avoid that, providing a custom interfaces LazyRenderKit and making html basic renderkit implements it. Then, in the init code we check for that interface and if is present, we use it to register the Renderer in a lazy way, otherwise we use the standard form. Add the required method to RenderKit looks like a good idea for include it in the spec.