Minecraft Skill System

I am building a Minecraft Plugin which adds multiple skills with corresponding XP. So far i have created a player class which contains the amount of XP a player has collected, it also has a method to write the players XP into a JSON file inorder to keep track of the XP even when the server shutsoff, the writing happens when a player logs off and when he logsback in the data gets loaded from the file into a new Player objekt created by the Player manager. The Player Manager keeps track of every play currently loged in on the server.

I have also started on creating the properties files in which the amount of XP gained for certain blocks mined, crops broken or crops harvested. Fitting to the files I have also written 2 listeners one for detecting when a block/crop has been broken and one to detect when a crop has been harvested, so right clicked. They add the amount of XP, which is defined in the properties files, to the player current XP count for the corresponding skill.