Help creating a global external variable

Hi, I'm here because I need help with something I do not know.
What I mean?
I would like to create variables that work in all my getConfig().getString("");
I have separated all classes.
I have an idea as it might be, correct me if I'm wrong.

IN THE MAIN CLASS

Code (Text):

public variable_player = variable_player.replace("%player%", player);

IN ANOTHER CLASS I MAY BE USED, WITH THIS.

Code (Text):

      private Main plugin;
   
      public ActionBarGlobal(Main pl){
          plugin = pl;
}

 

Sorry for my bad english, i speak spanish