I think Google has a really compelling argument that using the Java APIs in what has become the world's dominant personal computing platform's primary development toolset has increased the value of the Java APIs.
Unfortunately, that's not really how that swings. If you make for example a movie adaptation of a book it might drive book sales, but your use is primarily a replacement for a commercial opportunity to sell the movie rights. Sun/Oracle was selling Java ME licenses, Android was pretty clearly created to avoid those license terms. If we first assume the API is copyrighted, that does not seem like a typical fair use. The purpose is not interoperability with Java, it's to substitute it so the character of use is also against it and clearly they replicate a substantial amount of the API. The only factor that really speaks in favor of fair use is the nature of the work, which is purely descriptive and necessary to achieve the same functional operation.
Part of me want to agree a little bit with Oracle though, clearly designing an API is a creative effort. It's not merely stating a bunch of facts where somebody else designing an API would have to come up with something very, very similar. But the whole purpose of an API is to have a standardized way to interact with it, like being able to copyright where the brake pedal goes so nobody else can put it in the same spot and have it work in the same way. Like, I can't really think of a non-fair way to use an API which is why it shouldn't be copyrighted in the first place.