As best as you can. I don't know why people keep asking this question, when the answer is obvious and exactly like all other contribution policies.
In this case, this is coming from Oracle, which holds the OpenJDK purse strings, so being found in violation is also likely to have financial consequences for the violator.
> I don't know why people keep asking this question
Asking how do you enforce a policy that is practically unenforceable is a legitimate question.
> I don't know why people keep asking this question
Well, because it's going to lead to witch hunts and drama and so on. I mean, not necessarily on this project, but the same-ish discussion is going on on many community based projects (debian was recently on the front page with 4 proposals, etc).