Role of super Keyword in Java Inheritance

Java 8Object Oriented ProgrammingProgramming

Parent class objects can be referred to using the super keyword in Java. It is usually used in the context of inheritance. A program that demonstrates the super keyword in Java is given as follows:

Example

 Live Demo

class A {
   int a;
   A(int x) {
      a = x;
   }
}
class B extends A {
   int b;
   B(int x, int y) {
      super(x);
      b = y;
   }
   void print() {
      System.out.println("Value of a: " + a);
      System.out.println("Value of b: " + b);
   }
}
public class Demo {
   public static void main(String args[]) {
      B obj = new B(7, 3);
      obj.print();
   }
}

Output

Value of a: 7
Value of b: 3

Now let us understand the above program.

The class A contains a data member a and constructor A(). The class B uses the extends keyword to derive from class A. It also contains a data member b and constructor B(). The method print() prints the values of a and b. A code snippet which demonstrates this is as follows:

class A {
   int a;
   A(int x) {
      a = x;
   }
}
class B extends A {
   int b;
   B(int x, int y) {
      super(x);
      b = y;
   }
   void print() {
      System.out.println("Value of a: " + a);
      System.out.println("Value of b: " + b);
   }
}

In the main() method in class Demo, an object obj of class B is created. Then the method print() is called. A code snippet which demonstrates this is as follows:

public class Demo {
   public static void main(String args[]) {
      B obj = new B(7, 3);
      obj.print();
   }
}
raja
Published on 15-Feb-2019 11:33:39
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