Java Short addition questions

Question

This may have already been answered in another post, but I just am not getting why something won\'t compile in my test Java app (1.7.0_01).

This compiles:

Answer 1

Seems the correct answer was removed for some reason: (short) a + a is equivalent to ((short) a) + a, you're looking for (short)(a + a).

Edit

The 'why' behind it is operator precedence, same reason why 1 + 2 * 3 is 7 and not 9. And yes, primitives and literals are treated the same.

You can't do Short s = 1; s += 1; because it's the same as a = a + 1; where a is converted to an int and an int can't be cast to a Short. You can fix the long version like so: a = (short) (a + 1);, but there's no way to get the explicit cast in there with +=.

It's pretty annoying.

Answer 2

Here is a good example:

public class Example {
    public static void main(String[] args) {
        Short a = (short) 17;
        a = (short) (a + a);
    }
}