Write a program in java to implement the concept of Abstract Class using Java.

Code

Abstract class

abstract class Shape {

 abstract double area();

}

class Circle extends Shape {

 double radius;

 Circle(double r) {

 radius = r;

 }

 double area() {

 return Math.PI * radius * radius;

 }

}

class Rectangle extends Shape {

 double length;

 double width;

 Rectangle(double l, double w) {

 length = l;

 width = w;

}

 double area() {

 return length * width;

 }

}

// Main class

public class AbstractClassExample {

 public static void main(String[] args) {

 Circle circle = new Circle(5);

 Rectangle rectangle = new Rectangle(4, 6);

 System.out.println("Area of Circle: " + circle.area());

 System.out.println("Area of Rectangle: " + rectangle.area());

 }

}