Aren't you unfairly privileging the idea of a Java program over that of a Java library? A wholly-packaged Java program may not have interoperability with Android, but lots of libraries don't have that problem. There are plenty of copyrighted works written in Java that are fully compatible with Android.

If they happen to be lucky enough to use the cherry picked features from OpenJDK (cause they are now using it, but only the parts/packages they care about), not taking advantage of newer JVM bytecodes and ideally written in a Java 7 style.

I don’t disagree at all, but the question isn’t “are there pieces of existing software that run on both” but “is that the reason that Google copied the API or is it a side effect?”

I'd argue that that is the wrong question, motive doesn't come into play in this law (specifically: The merger doctrine). You should rather be asking the hypothetical version. If someone tried to make a second system that could run the software, would they have had to copy the API? If so the API is not copyrightable.

The existence of those works that run on both means you really need to start coughing up evidence for your repeated assertion that Google's motives were strictly about something else.

>they’re copying the Java API to provide a familiar environment for Java developers

Well, that's a difference without meaning. Familiarity with the syntax is important but we're not talking about copyrighting the language structure and syntax.

The other aspect is that of the wider ecosystem. Once you commit to Java, you have to reimplement the existing APIs because every Java library relies on those APIs. And it is that ecosystem that is the true value prop. The API itself isn't special itself (in fact, the Java one is frequently maligned for how bad it is), and devs adapt quickly to different ones when they move to another programming language. There would be no point in selecting the Java language without being able to partake in the ecosystem, no matter how brilliant the API design is. And if it was brilliant, they could have aped it in another language (Dart?) ... I'm making an assumption that presumably adapting the API to another language would be fine by you? Because if not, the mess you would cause in the industry would be immeasurable.