Fighter Rankings

import java.util.*;

public class Fighter implements Comparator<Fighter> {

   public String name;
   public int atk, def, powerLevel;
   public static List<Fighter> fighters = new ArrayList<Fighter>();

   public Fighter(String name, int atk, int def){
      this.name = name;
      this.atk = atk;
      this.def = def;
      this.powerLevel = CalculatePowerLevel(atk, def);
      }

   public int CalculatePowerLevel(int atk, int def){
      return atk * def;
   }

   public static void main(String[] args){
      fighters = Arrays.asList(new Fighter ("Krillin", 50, 20), new Fighter("Yamcha", 20, 30));
      Collections.sort(fighters, new Fighter("None", 1, 1));
      System.out.println("The strongest fighters by power level are: ");
      for(Fighter fighter : fighters) System.out.println(fighter.name);
   }

   @Override
   public int compare(Fighter a, Fighter b){
      return b.powerLevel - a.powerLevel;
}

}