Making a generic comparator class [closed]

Answer 1

The closest thing you can do to this is a Comparator that can compare any objects that implement the Comparable interface:

class NaturalComparator> implements Comparator {
  public int compare(T a, T b) {
    return a.compareTo(b);
  }
}

That's really the closest you can do: only Comparable objects have the "natural ordering" you're trying to model here. But generally, once you have Comparable objects, you don't necessarily need a Comparator: for example, Collections.sort can take either a List with a Comparator, or a List with Comparable elements.