Inheritance

In object-oriented programming, a subclass is a class that inherits properties and methods from a parent class, also known as a superclass. A subclass can add new properties and methods to the ones it inherits from the superclass, allowing for greater flexibility and reusability in software development.

In Java, the keyword is used to create a subclass. When a subclass is created, it inherits all of the properties and methods of the parent class, and can also add its own new properties and methods.

Here's an example of how a subclass works in Java:

public class Animal {
    public void makeSound() {
        System.out.println("The animal makes a sound");
    }
}

public class Dog extends Animal {
    public void makeSound() {
        System.out.println("The dog barks");
    }

    public void fetch() {
        System.out.println("The dog fetches a ball");
    }
}

public class Main {
    public static void main(String[] args) {
        Animal animal = new Animal();
        animal.makeSound(); // Output: "The animal makes a sound"

        Dog dog = new Dog();
        dog.makeSound(); // Output: "The dog barks"
        dog.fetch(); // Output: "The dog fetches a ball"
    }
}

In this example, we define a superclass Animal with a single method makeSound(), which prints a message to the console. We then define a subclass Dog that extends Animal, and adds a new method fetch().

In the Main class, we create an object of the Animal class and call the makeSound() method, which prints "The animal makes a sound". We then create an object of the Dog class and call the makeSound() and fetch() methods, which print "The dog barks" and "The dog fetches a ball" respectively.

Try to think of other possible Inheritance scenarios. What are some classes that could inherit from a more generic parent class? Here are a few we can think of:

• Developer, TeamLeader, and Manager could inherit from an Employee parent class
• HondaCivic could extend from a Car parent class
• Poodle could extend from Dog. Dog could also extend from Animal!