What is super keyword in Java: Explanation and Examples

In Java, the super keyword is used to refer to the parent class of the current object. It allows access to the parent class's methods, constructors, and variables, especially when they are overridden or hidden in the child class.

How It Works

Imagine you have a family tree where a child inherits traits from their parents. In Java, classes can inherit from other classes, called parent or superclass. The super keyword acts like a direct link to the parent, letting the child class access or call things that belong to the parent.

For example, if a child class has a method with the same name as the parent, using super lets you call the parent's version instead of the child's. It also helps when you want to use the parent's constructor to set up the object before adding more details in the child.

This keyword helps keep things clear and organized, especially when you want to build on or change behavior inherited from a parent class.

Example

This example shows a parent class Animal and a child class Dog. The Dog class uses super to call the parent constructor and method.

java

class Animal {
    String name;
    Animal(String name) {
        this.name = name;
    }
    void sound() {
        System.out.println("Animal makes a sound");
    }
}

class Dog extends Animal {
    Dog(String name) {
        super(name); // Calls Animal constructor
    }
    @Override
    void sound() {
        super.sound(); // Calls Animal's sound method
        System.out.println("Dog barks");
    }
}

public class Main {
    public static void main(String[] args) {
        Dog dog = new Dog("Buddy");
        dog.sound();
    }
}

Output

Animal makes a sound
Dog barks

When to Use

Use super when you want to:

• Call a parent class constructor to reuse its setup code.
• Access a parent class method that is overridden in the child class.
• Refer to a parent class variable if it is hidden by a child class variable.

Real-world use cases include extending a base class with common features and customizing behavior in child classes without losing the original functionality. For example, in a game, a Character class might have basic movement, and a Player class can use super to keep that movement but add special moves.

Key Points

• super refers to the immediate parent class.
• It helps access overridden methods and hidden variables.
• It is used to call parent constructors.
• Using super keeps code clear and avoids duplication.

Key Takeaways

The super keyword accesses parent class methods, variables, and constructors.

Use super to call overridden methods or parent constructors from a child class.

super helps avoid code duplication and keeps inheritance clear.

It always refers to the immediate parent class in the inheritance chain.