Main issue is making people move away from one language to another. You'd have to let people use their existing code base with the new language (like apple did with swift). Could it be possible without another similar lawsuit?
Call them "legacy apps" and run them over a compatibility layer. Hardware will gradually get good enough to run the old Java apps without hiccups, and the apps that get translated to Go will run about as fast as the Java-Android versions [citation needed], but with oodles of memory to spare.
if the API is copyrightable, your "compatibility layer" would also infringe.