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

Here is a good example:

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