$0 to reg fee.
Java is a trademark. I don't know if they enforce it but it is a trademark.
Also for a tutorial site, there are 100 better names I could think of than this one. RefactorJava and RefactoringJava are better because refactor is actual coding terminology. And they're both avail for hand-reg.
I wonder if using the name Java on a tutorial site is 'breaking trademark rules'.