Abstract Class Example
This program demonstrates abstract class usage.
Problem Statement
Write a Java program to define abstract class Shape with abstract method area().
Source Code
| 1 | abstract class Shape { |
| 2 | abstract void area(); |
| 3 | } |
| 4 | class Circle extends Shape { |
| 5 | int r; |
| 6 | Circle(int r){ this.r=r; } |
| 7 | void area(){ System.out.println("Circle area: "+(3.14*r*r)); } |
| 8 | } |
| 9 | public class AbstractClass { |
| 10 | public static void main(String[] args) { |
| 11 | System.out.println("Eduinq Abstract Class"); |
| 12 | Shape s=new Circle(5); |
| 13 | s.area(); |
| 14 | } |
| 15 | } |
Program Output
Eduinq Abstract Class Circle area: 78.5
Explanation
Abstract class defines common structure but leaves implementation to subclasses. - Circle provides its own implementation of area(). - Abstract classes enforce design contracts, ensuring subclasses implement required methods. Conclusion: Shows how to use abstract classes in Java.