private static void sortListGCal(List<GregorianCalendar> list) {

    long start = System.nanoTime();
    Collections.sort(list);
    long end = System.nanoTime();
    System.out.println("GCalendar: Sort:   " + NF.format(end - start) + " ns");
    result("GregCal-S", end - start);
  }