Google is using Java language and its API, not JVM or its libs. Google never called Android a Java compatible or Java. Google has written all of its libs and the Dalvik VM.

Now look at this story, it's a company claiming to be Android compatible and using Android runtimes. All they did was a fork and customization of Android. Not there's anything wrong with that, but if you are a member of OHA you agree not to do it.

So there you go:

Google never agreed to anything, Acer did.

Google wrote code and used non-copyrightable part of Java, Alibaba did not (but they still didn't do anything wrong).

Google got sued, Acer/Alibaba did not.