26 : Inheritance Part 2 -Java Programming in Urdu

if you are new to this web we suggested review first Inheritance Part 1

 Inheritance Part 2

The super keyword

The super keyword is similar to this keyword. Following are the scenarios where the super keyword is used.

• It is used to differentiate the members of super-class from the members of subclass, if they have same names.
• It is used to invoke the super-class constructor from subclass.

Example:3 A program that demonstrates the usage of the super keyword.

class Super_class {
   int num = 20;

   // display method of superclass
   public void display() {
      System.out.println("This is the display method of superclass");
   }
}

public class Sub_class extends Super_class {
   int num = 10;

   // display method of sub class
   public void display() {
      System.out.println("This is the display method of subclass");
   }

   public void my_method() {
      // Instantiating subclass
      Sub_class sub = new Sub_class();

      // Invoking the display() method of sub class
      sub.display();

      // Invoking the display() method of superclass
      super.display();

      // printing the value of variable num of subclass
      System.out.println("value of the variable named num in sub class:"+ sub.num);

      // printing the value of variable num of superclass
      System.out.println("value of the variable named num in super class:"+ super.num);
   }

   public static void main(String args[]) {
      Sub_class obj = new Sub_class();
      obj.my_method();
   }
}

Output:

This is the display method of subclass
This is the display method of superclass
value of the variable named num in sub class:10
value of the variable named num in super class:20