interface Hond {
   void blaf();
    //...
}

class SintBernard implements Hond {
    public void blaf() {
        System.out.println("Woef woef");
    }
}

class Tekkel implements Hond {
    public void blaf() {
        System.out.println("Kef kef");
    }
}

public class THond2 {
    public void doeJeWerk(Hond h) {
        h.blaf();
    }
    public static void main(String[] s) {
        THond2 test=new THond2();
        Tekkel harry=new Tekkel();
        SintBernard bor=new SintBernard();
        for (int i=0; i<10; ++i)
            if (i%3==0)
                test.doeJeWerk(harry);
            else
                test.doeJeWerk(bor);
   }
}