The `super` Keyword in Java

What is the `super` Keyword in Java?

1. To access superclass instance variables: Used when a subclass and superclass have variables with the same name.
2. To invoke superclass methods: Used to call a method from the parent class, especially when the subclass has overridden it.
3. To invoke the superclass constructor: Used to call the constructor of the parent class from the subclass constructor.

// Superclass
class Animal {
    String color = "White"; // 1. Superclass instance variable

    Animal() { // 3. Superclass constructor
        System.out.println("Animal is created");
    }

    void eat() { // 2. Superclass method
        System.out.println("Animal is eating...");
    }
}

// Subclass
class Dog extends Animal {
    String color = "Black"; // Subclass instance variable with the same name

    Dog() {
        super(); // 3. Invokes the parent class constructor (Animal())
        System.out.println("Dog is created");
    }
    
    void printColor() {
        System.out.println("Dog color is: " + color); // Prints color of Dog class
        System.out.println("Animal color is: " + super.color); // 1. Accesses color of Animal class
    }

    @Override
    void eat() {
        System.out.println("Dog is eating bread...");
        super.eat(); // 2. Invokes the parent class eat() method
    }
}

public class TestSuper {
    public static void main(String[] args) {
        Dog d = new Dog();
        d.printColor();
        d.eat();
    }
}
        

Animal is created
Dog is created
Dog color is: Black
Animal color is: White
Dog is eating bread...
Animal is eating...