Funky Java :)

AbstractClass.java

public abstract class AbstractClass {

    public void printClass() {
        System.out.println(this.getClass().getName());
        System.out.println(getClass().getName());
    }
}

Alternative-Version.java

// Here's an alternative to abstract class.
public interface AbstractClass {

    default void printClass() {
        System.out.println(this.getClass().getName());
        System.out.println(getClass().getName());
    }

    void foo();
}

public class Main {

    public static void main(String... args) {
        AbstractClass cat = new Cat();
        AbstractClass dog = new Dog();
        AbstractClass abstractClass = () -> {};
      
        cat.printClass();
        dog.printClass();
        abstractClass.printClass();
    }
}

// Same Cat and Dog classes using implements instead of extends with empty foo methods.
// This one is even funkier (But java 8+ only).

Cat.java

public class Cat extends AbstractClass {}

Dog.java

public class Dog extends AbstractClass {}

Main.java

public class Main {

    public static void main(String... args) {
        AbstractClass cat = new Cat();
        AbstractClass dog = new Dog();
        AbstractClass abstractClass = new AbstractClass() {};

        cat.printClass();
        dog.printClass();
        abstractClass.printClass();
    }
}