It is an unofficial side project. Same as what the go team is doing with their language. I don't expect the Android team to switch language soon. In their own

It is an unofficial side project. Same as what the go team is doing with their language. I don't expect the Android team to switch language soon. In their own words, the engineering cost to rewrite the whole stack in another language is just too big, especially since they are not convinced that it is an obvious way to improve the platform. In the near future, I would be less surprised to see them adopt Kotlin : it fixes many of java weaknesses, accepts java classes and produces compatible bytecode.