code: public static <T extends Comparable<? super T>, L extends List<T>> L sortThis(L list)
      {
          if (list instanceof MutableList<?>)
          {
              ((MutableList<T>) list).sortThis();
          }
          else if (list instanceof ArrayList)
          {
              ArrayListIterate.sortThis((ArrayList<T>) list);
          }
          else
          {
              if (list.size() > 1)
              {
                  Collections.sort(list);
              }
          }
          return list;
      }
docs: SortThis is a mutating method.  The List passed in is also returned.