Return type of method in subclass differ from return type in parentclass

[Oddbjorn Lona]

This code does not compile.

  
class A
{
   Integer print()
   {
   System.out.println("A");
   return 0;
   }
}

class B extends A
{
   int print()
   {
   super.print();
   System.out.println("B");
   return 1;
   }
  
   public static void main( String[] args)
   {
   A obj = new B();
   obj.print();
   }
}

The whizlab answer states that the given code does not compile because the method in the subclass differ only in the return type; its not legal. If the argument had been different, it would have been a case of overloading.

In my opinion it does not compile because of the "int" of the print method is not a identical to Integer or one of (Integers) subclasses. Thats why you cannot compile this.

What do you say?

Thanks.

[Sebastian Janisch]

So both your and whizlabs statements are correct.

To override a method you need to keep the exact same signature, except for covariant return types and exceptions that need to be the same, narrowed or not existent at all in the overriding class.

[Ankit Garg]

I think you've understood it right. If the return type of the overriding method was Integer (or a sub-class as per covariant return types, but Integer class is final so not applicable here) then the code would've compiled fine. The answer in whizlabs also says the same thing, but they also explain that if the print method in sub-class had different arguments, then there would've been overloading and thus the code would've compiled fine...