Java 'super' Keyword Tutorial

Usage of Java 'super' Keyword

• 1. To refer immediate parent class instance variable

  We can use super keyword to access the data member or field of parent class. It is used if parent class and child class have same fields.

• 2. To invoke immediate parent class method

  The super keyword call can be used to invoke parent class method. It should be used if subclass contains the same method as parent class.

  class Animal {
    void eat() { System.out.println("eating..."); }
  }
  
  class Dog extends Animal {
    void eat() { System.out.println("eating bread..."); }
    void bark() { System.out.println("barking..."); }
    void work() {
      super.eat();
      bark();
    }
  }

• 3. To invoke immediate parent class constructor

  The super() call can be used to invoke the parent class constructor.
  Note: `super()` must be the first statement in constructor.

  class Bird {
      private String name;
  
      public Bird(String name) {
          this.name = name;
      }
  }
  
  class Parrot extends Bird {
      public Parrot(String name) {
          super(name);
      }
  }