Super Keyword in Java Explained

The super keyword in Java is a reference used inside a subclass to refer to its immediate parent (superclass). It is commonly used to access parent class constructors, methods, and variables that have been hidden or overridden.

Calling the Parent Class Constructor

When a subclass is created, super() can be used to explicitly call the parent class's constructor, which must be the first statement inside the subclass constructor.

class Animal {
    Animal(String name) {
        System.out.println("Animal: " + name);
    }
}

class Dog extends Animal {
    Dog(String name) {
        super(name); // calls Animal's constructor
        System.out.println("Dog created");
    }
}

Accessing Parent Class Methods

If a subclass overrides a method from its parent, super.methodName() can be used inside the subclass to still call the parent's version of that method.

class Vehicle {
    void start() { System.out.println("Vehicle starting"); }
}

class Car extends Vehicle {
    void start() {
        super.start(); // calls Vehicle's start()
        System.out.println("Car starting");
    }
}

Accessing Parent Class Variables

super can also be used to access a field from the parent class when the subclass has a field with the same name, avoiding ambiguity between the two.

• super() — calls the parent class constructor
• super.method() — calls the parent class's version of a method
• super.variable — accesses the parent class's field