import java.util.Collections;import java.util.LinkedList;import java.util.List;public class Test {     List list  =   new  LinkedList();     public   static   void  main(String[] args)  {        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     }     }