another_troll.java

public static class MyFunction implements Callable<Integer> {

  private int a;
  private int b;
  
  public MyFunction(int a, int b) {
      this.a = a;
      this.b = b;
  }
  
  @Override
  public Integer call() throws Exception {
      return this.a + this.b;
  }
}
  
public static void main(String... args) throws Exception {
  Map<String, Callable> superhero = new HashMap<>();
  
  superhero.put("doHero", new MyFunction(3, 5));
  
  System.out.println(superhero.get("doHero").call());
}