If Google has the copyright of the code their own developers wrote then they can relicense any code they wrote, including GPL.
Edit Also they will probably try to replace Java with Dart to get around the Java/Oracle problem
Edit Also they will probably try to replace Java with Dart to get around the Java/Oracle problem
However, it might mean that they have to re-implement big parts of the Android runtime, or even do clean-room implementations by people not previously involved in those projects, to prevent legal attacks on the inevitably-similar code that results.
one may view Google's current emphasis on Kotlin in the same light