This plugin prevents players from different clients from entering the server with the same playername.
The first time a player enters the server, the player's name and UUID will be recorded in the database.
After that, players will get their UUID when they enter the server again, and compare it with the one in the database. If they are different, they will be banned from entering the server.
You can edit the displayed text in config.yml
Commands
View help messages: /uniqueuuid help Reload plugin: /uniqueuuid reload
Others
This is my first plugin, please let me know if you have any suggestions.