Google and Oracle and a bunch of other companies all make cars. All of the cars have a gearshift with the same pattern, because long ago the company who built the first car encouraged other carmakers to copy their design. But then Oracle buys the company who built the first car and tries to sue Google (and only Google) for copying their shift pattern.
My understanding, which may be incorrect, is that Sun intended for their JVM to be the reference version, and they envisioned a lot of companies creating their own competing (but compatible) JVMs.
I don't recall any hints or suggestions "copying" the Java API would be a problem. I believe Sun planned on making money by charging for Java implementations to be tested against the TCK in order to earn the Java label.