code: static <T> void bucketSort(final List<? extends T> c, final Comparator<? super T> cmp) {
          if (N.isNullOrEmpty(c)) {
              return;
          }
  
          bucketSort(c, 0, c.size(), cmp);
      }
docs: Note: All the objects with same value will be replaced with first element with the same value.
  
  @param c
  @param cmp