public static <T> void sort(List<T> l, Comparator<? super T> c)
public static <T extends Comparable<? super T>> void sort(List<T> l)
  public static <T> void sort(List<T> l, Comparator<? super T> c)  {    T[] a = (T[]) l.toArray();    Arrays.sort(a, c);    ListIterator<T> i = l.listIterator();    for (int pos = 0, alen = a.length;  pos < alen;  pos++)      {	i.next();	i.set(a[pos]);      }  }