Why can't I pass in java an array of short to method accepting array of int?

Question

I have a method, that accepts int[] parameter. I want to pass it an array of shorts. But all I get is "incompatible types: short[] cannot be converted to int[]". Why is that? an example:

short[] arr = new short[2];
arr[0] = 8;
arr[1]=9;
example(arr);

example(int[] anArray){
}

As far as I know, short to int is just widening, so it should be typecasted automatically, shouldn't it? How to pass it then? Thanks.

Answer 1

You can't do that, because a short[] is not an int[]. Also, a short is not an int, it's just that Java allows a primitive widening conversion to allow a short to be widened to an int. However, there is no such primitive widening conversion for arrays of primitive types.

That forces a few core Java APIs to accept many different types of primitive arrays, such as Arrays.sort, which has overloads for many different types of primitive arrays.

If you'd like to do the same thing to a short[] that you've already done to an int[], you must provide an overloaded method, such as example(short[] anArray).

The JLS, Section 5.1, specifies all types of conversions, and specifically disallows those not listed in 5.1.12, "Forbidden Conversions":

> Any conversion that is not explicitly allowed is forbidden.

Conversions between types of primitive arrays are not listed, so they're not allowed.