Collections工具类

import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

public class Test19 
{
    public static void main(String[] args) 
    {
           List list=new LinkedList();//多态
           for(int i=0;i<9;i++)//循环添加值
           {
               list.add("a"+i);
           }
           System.out.println(list);
           
           Collections.shuffle(list);//随机排列
           System.out.println("随机排列:"+list);
           
           Collections.sort(list);//升序排列
           System.out.println("升序排列:"+list);
           
           Collections.reverse(list);
           System.out.println("逆序排列:"+list);
    }
}