JAVA集合存放的是对象还是对象引用？

2018-06-18 03:46:26来源：未知阅读 ()

问题：添加一个对象到集合中时，集合里面存放的是对象的引用还是对象本身？

答：对象的引用。以下代码可以证明：

 1 import JAVA.util.ArrayList;
 2 import JAVA.util.List;
 3 
 4 public class Test5 {
 5     public static void main(String args[]){
 6         List<User> userList1 = new ArrayList<User>();        
 7         List<User> userList2 = new ArrayList<User>();    
 8         User user1 = new User();
 9         userList1.add(user1);        
10         userList2.add(user1);
11         
12         System.out.println("SET VALUE FOR USERLIST2:");        
13         for(User user: userList2){
14             user.setName("name");
15             user.setPassword("password");        
16         }
17         System.out.println("PRINT VALUE FOR USERLIST1:");
18         for(User user: userList1){
19             System.out.println(user.getName());            
20             System.out.println(user.getPassword());            
21         }        
22     }
23     
24     public static class User{
25         private String name;
26         private String password;
27         
28         public String getName() {
29             return name;
30         }
31         public void setName(String name) {
32             this.name = name;
33         }
34         public String getPassword() {
35             return password;
36         }
37         public void setPassword(String password) {
38             this.password = password;
39         }
40     }
41 }