对ArrayList实例对象中的元素进行排序

import java.util.*;

public class TestSort {
public static void main(String[] args) {
// TODO Auto-generated method stub
ArrayList a1 = new ArrayList();
a1.add(new Integer(1));
a1.add(new Integer(3));
a1.add(new Integer(2));
System.out.println(a1.toString());
Collections.sort(a1);
System.out.println(a1.toString());
}
}