I do not have expierence on java and I was wondering can any pro really do this? Because it really would change minecraft especially xAuth with whitelist united would be useless I know the ip hackers but would it be possible c'mon people?
I don't see the use for this. If you have a real minecraft, as I'm sure you do, you can just whitelist with usernames. Also, whitelisting with Ip's isn't a good idea because Ip's change all the time.
And what if, like in my situation, minecraft.net is down and you can only go on your server with the "Player" account, and people keep connecting with that acc and kicking you out? You can't just whitelist Player, otherwise you can't get on. You can ban it, and unban whenever you need to go on, but that's too complicated. Think about it next time before replying something stupid. Peace