Java instanceof

BadFoo.java

abstract class BadFoo {

  static class Bar extends BadFoo {
    int bar;

    private Bar(int bar) {
      this.bar = bar;
    }

  }

  static class Baz extends BadFoo {
    String baz;

    private Baz(String baz) {
      this.baz = baz;
    }

  }

  static void handle(BadFoo f) {
    if (f instanceof Bar) {
      Bar b = (Bar) f;
      System.out.println("I have " + b.bar + " bars");
    } else if (f instanceof Baz) {
      Baz b = (Baz) f;
      System.out.println("I have the " + b.baz + " baz");
    }
  }

  public static void main(String[] args) {
    handle(new Bar(42));
    handle(new Baz("Luhrmann"));
  }
}