Creating methods that work with instances of different subclasses

After we declare all the new classes, we will create the following two methods that receive a VirtualAnimal instance as an argument, that is, a VirtualAnimal instance or an instance of any subclass of VirtualAnimal. Each method calls a different instance method defined in the VirtualAnimal class: printAverageNumberOfBabies and printAsciiArg. The code file for the sample is included in the java_9_oop_chapter_07_01 folder, in the example07_02.java file.

void printBabies(VirtualAnimal animal) {
    animal.printAverageNumberOfBabies();
}

void printAsciiArt(VirtualAnimal animal) {
    animal.printAsciiArt();
}

Then the following lines create instances of the next classes: Cockatiel, VirtualDomesticRabbit, and MaineCoon. The code file for the sample is included in the java_9_oop_chapter_07_01 folder, in the example07_02.java file.

Cockatiel tweety = 
    new Cockatiel(3, "White", "Tweety");
VirtualDomesticRabbit bunny = 
    new VirtualDomesticRabbit...