List list  =   new  LinkedList();

         for  ( int  i  =   0 ; i  <   9 ; i ++ )  {

             list.add( " a " + i);

         }

         Collections.sort(list); // 顺序排列

         System.out.println(list);

         Collections.shuffle(list); // 混乱的意思

         System.out.println(list);

         Collections.reverse(list); // 倒序排列

         System.out.println(list);

         System.out.println(Collections.binarySearch(list,  " a5 " )); // 折半查找