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Can someone explain me why if a run this code 

public class MainClass{

   public void method(Object obj){
       System.out.println("+++++++++obj");
   }

   public void method(A a){
       System.out.println("**********a");
   }

   public static void main(String[] args){
       new MainClass().method(null);
   }
}

I get this result:

**********a

How can a null reference be resolved to an "A" object reference?

laks.it
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    `null` can be resolved to anything and thus the most specific method will be used. Add a method with parameter type `B` and the compiler should complain about ambiguous parameters. – Thomas Sep 25 '15 at 09:19
  • This isn't overriding, it's overloading - and it doesn't seem *terribly* obscure to me. Would you expect `A a = null;` to fail to compile? – Jon Skeet Sep 25 '15 at 09:23

1 Answers1

6

Most specific method chooses at run. A is more specific than Object and 

A a = null;

is valid.

Hence when you pass null, its choosing (A a).

Here is the Language specification

Suresh Atta
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