Google's implementation is a clean-room one, based on the former Apache Harmony and isn't a derivate of OpenJDK. If it would have been a derivate work of OpenJD

Google's implementation is a clean-room one, based on the former Apache Harmony and isn't a derivate of OpenJDK. If it would have been a derivate work of OpenJDK, then the GPLv2 license would have protected them. And no, they didn't violate the GPL. When a copyright owner releases code under an open-source license, that doesn't mean that they are waiving their copyrights. Open-source is not the public domain.