Covariant Return Types in Java Method Overriding with examples

Covariant Return Types HackerRank solution in Java

Java allows for Covariant Return Types, which means you can vary your return type as long you are returning a subclass of your specified return type. 

Learn more about Method Overriding and Covariant Return Types with Examples :

• Method Overriding and covariant return type in Java
  

The name comes from the fact that the type of the return is allowed to vary in the same direction that you subclass.  

See problem description on HackerRank :

• Covariant Return Types Problem Description

Lets see solution.

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

//Complete the classes below
class Flower {
   String whatsYourName () {
       return "I have many names and types.";
   }
}

class Jasmine extends Flower {
    String whatsYourName () {
       return "Jasmine";
    }
}

class Lily extends Flower {
    String whatsYourName() {
       return "Lily";
    }
}

class Region {
     Flower yourNationalFlower() {
        return new Flower();
     }
}

class WestBengal extends Region {
     Jasmine yourNationalFlower() {
       return new Jasmine();
     }
}

class AndhraPradesh extends Region {
     Lily yourNationalFlower() {
       return new Lily();
     }
}


public class Solution {
  public static void main(String[] args) throws IOException {
      BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
      String s = reader.readLine().trim();
      Region region = null;
      switch (s) {
        case "WestBengal":
          region = new WestBengal();
          break;
        case "AndhraPradesh":
          region = new AndhraPradesh();
          break;
      }
      Flower flower = region.yourNationalFlower();
      System.out.println(flower.whatsYourName());
    }
} 

 

Happy Coding.