method overloading and passed arguments

[nancy nant]

Hello,
I'm preparing for SCJP 5 and have doubt about overloading methods.
I tried to compile this code:

public class Main {
public static void test(int... a){System.out.println("int array");}
public static void test(Number... a){System.out.println("Number");}

public static void main(String[] args) {
test(new byte[]{2,3});
}
}


and i got compile time error: cannot find symbol: method test(byte[])

I expected that the result would be:int array. Can someone explain me why is this happened.

Nancy

[Ankit Garg]

There is a compile time error as an byte[] cannot be assigned to int[]. They are both sub classes of Object and are siblings i.e. they are not parent child of one another.

      Object
 -------+--------------------------------
 |             |           |            |
int[]        byte[]      Number      Object[]
                                   -----+-----
                                   |         |
                       other array types   Number[]

As you might know, that object references can be assigned to each other only if they have a parent child relationship. This is not the case here so it is giving you an error.

[nancy nant]

Thank you Ankit!!!

[Bert Bates]

Ankit -

That is some seriously good ascii art!

- Bert

[Fabio Nascimento]

You can pass a byte when you are expecting an int because bytes can be promoted to ints, but you cant pass an array of bytes when you expect an array of ints.

[Ankit Garg]

Originally posted by Bert Bates:
Ankit -

That is some seriously good ascii art!

- Bert

Thanks Bert. That is a very big complement for me!