错误：（107、9）Java：找不到符号symbol：方法loadConfiguration（）？

Question

所以我试图制作一个bukkit插件，当我尝试将工件构建到jar中时遇到这些错误。

    Error:(107, 9) java: cannot find symbol
  symbol:   method loadConfiguration()
  location: class net.minenite.warzairdrops.MainClass

    Error:(117, 13) java: cannot find symbol
  symbol:   method log(java.lang.String,java.util.logging.Level)
  location: class net.minenite.warzairdrops.MainClass


    Error:(120, 9) java: cannot find symbol
  symbol:   method log(java.lang.String,java.util.logging.Level)
  location: class net.minenite.warzairdrops.MainClass

这里是我的代码：

Main Class

CommandsClass