My thoughts are Sun is doing this to push more developer (Python developers) to use its VM and API, as a way to better compete with .Net (not a sin for sure)

But I am not that convinced they now love Python. Plus they only hired one developer, so it feels more like a marketing move. i.e. they dont seem in a hurry if they only hired just one developer to do it

Better support for Dynamic languages for the JVM is surely a good thing.