Creating an abstract base class

First, we will create the abstract class that will become our base class for the other classes. The following lines show the code for the VirtualAnimal abstract base class in Java 9. The abstract keyword before class indicates to Java that we are creating an abstract class. The code file for the sample is included in the java_9_oop_chapter_06_01 folder, in the example06_01.java file.

public abstract class VirtualAnimal {
    public final int age;

    public VirtualAnimal(int age) {
        this.age = age;
        System.out.println("VirtualAnimal created.");
    }

    public abstract boolean isAbleToFly();

    public abstract boolean isRideable();

    public abstract boolean isHerbivore();

    public abstract boolean isCarnivore();

    public abstract int getAverageNumberOfBabies();

    public abstract String getBaby();

    public abstract String getAsciiArt();

    public void printAsciiArt() {
        System.out.println(getAsciiArt());
    }

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