Soyut sınıf

/**
 * Abstract class for animals
 */
public abstract class Animal {
    
    /**
     * The method that let's the animal make the sound
     * @return The sound
     */
    abstract public String makeASound();

}

/**
 * Class for all cats
 */
public abstract class Cat extends Animal {

    /* (non-Javadoc)
     * @see Animal#makeASound()
     */
    @Override
    public String makeASound() {
        return "Miyaaav!";
    }
}

/**
 * Class for all dogs
 */
public class Dog extends Animal {
    /* (non-Javadoc)
     * @see Animal#makeASound()
     */
    @Override
    public String makeASound() {
        return "Hav hav!";
    }
}

/**
 * Turkish Van cat
 */
public class TurkishVan extends Cat {
}

/**
 * Test class
 */
public class AnimalsTest {

    /**
	 * Test method for animals
     * @param args
     */
    public static void main(String[] args) {
        Animal vanKedisi = new TurkishVan();
        Animal karabas = new Dog();
        
        System.out.print("Karabas " + karabas.makeASound() + " dedi.\n");
        System.out.print("Mirnav " + vanKedisi.makeASound() + " dedi.");
    }
}