Hashmap Saving keeps making new Hashmaps..

Okay basically I got a scoreboard saving thing all up and running
However, It ment to be everytime they join they get 1 point
When the server reloads, or turns off it will save it to a file,
and then when turned on again it will load it,
However it keeps making new lines every restart or shutdown. For example, If i restart the server 20 times, there are 20 of mu username on my config file.. Please help, here is my code http://pastebin.com/nXGNvtK8

 

It gets the list, adds more names to it, and saves it. What did you expect?

 

@Garris0n ​

Well yeah, But how do I get it so it only makes 1 save per user?

 

Don't add it to the list if it's already in the list?

 

...

 

Tried that, I tried to say, if it is in the list, then change that line to the thing, But it didn't do anything