[BoDlulu]

I seem to remember that the 98 case was a trademark violation. Microsoft used the Java brand even though their implementation wasn't compliant (it was a derivative) - which was a big issue for Sun since one of the main point of Java is compatibility ("Write once, run everywhere").

Google however made sure to always be clear about "the Java Programming Language" or such safe phrase that makes clear that they're not the official thing.

[AnimalMuppet]

Correct. Microsoft could make J++ or whatever; they just couldn't call it Java.

The particular issue was that Microsoft was extending some of the Java language (and maybe com.sun?) classes. If you used any of their extensions, then you had code that could only be compiled with Microsoft's compilers, and you were locked in. (The "extend" phase, which is then leveraged for the "extinguish" phase.)