Why is my simple comparator broken?

Question

I have a class, which I have simplified to this:

final class Thing {
    private final int value;
    public Thing(int value) {
        this.value = value;
          


        

Answer 1

You cannot use minus to create the comparison. You'll overflow when the absolute difference exceeds Integer.MAX_VALUE.

Instead, use this algorithm:

int compareInts( int x, int y ) {
  if ( x < y ) return -1;
  if ( x > y ) return 1;
  return 0;
}

I like to have this function in a library for such purposes.