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

    StringBuilder buf = new StringBuilder();
    SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd", Locale.ENGLISH);
    long start = System.nanoTime();
    for (GregorianCalendar gcal : list) {
      buf.setLength(0);
      buf.append(format.format(gcal.getTime()));
    }
    long end = System.nanoTime();
    System.out.println("GCalendar: Format: " + NF.format(end - start) + " ns" + " " + buf);
    result("GregCal-P", end - start);
  }