Agree with GG. I'm on 7/64 Home Premium, FF 12 - I just stopped the auto updates, so not on 13. Use M/S Sec. Essentials.
Java plug in same no as GG, and working OK as far as I can tell.
Java and FF did appear to have a conflict on my machine a couple of FF updates ago, but fine now. Had to delete Java completely and start again.