code: public int compare(Object o1, Object o2) {
          int m1 = ((int[])o1)[0];
          int m2 = ((int[])o2)[0];
          if (m1 < m2)
              return -1;
          if (m1 == m2)
              return 0;
          return 1;
      }
docs: The method used to sort the metrics array.
  @param o1 the first element
  @param o2 the second element
  @return the comparison