我对数组列表中的克隆概念感到困惑。 例如：

Balloon green = new Balloon("Green",new Address("greenState","greencity"));
Balloon green2 = (Balloon)green.clone();
green.setColor("NewGreen");
System.out.println(green);
System.out.println(green2);//color not affected in copy as color is of String type.
                           //Immutable objects are not shallow copied.
green.getaddress().state="helloState";
System.out.println(green);
System.out.println(green2);//Address does get affected

输出：-

  

气球[color = NewGreen地址=地址{state =   greenState，city = greencity}]
气球[color =绿色Address =地址   {state = greenState，city = greencity}]
气球[color = NewGreen   地址=地址{州= helloState，城市= greencity}]   
气球[颜色=绿色地址=地址{州= helloState，城市=   greencity}]

这很清楚。但是现在让我们获取数组列表。

Balloon red = new Balloon("Red",new Address("redState","redCity")); 
Balloon blue = new Balloon("Blue",new Address("blueState","blueCity"));
Balloon yellow = new Balloon("yellow",new Address("yellowState","yellowCity"));

ArrayList<Balloon> list = new ArrayList<>();
list.add(red);
list.add(blue);
list.add(yellow);
ArrayList<Balloon> listCopy = (ArrayList<Balloon>)list.clone();
Balloon green = new Balloon("Green","greencity"));

list.get(1).setColor("color");

list.add(green);
System.out.println(list);
System.out.println(listCopy);

输出：-

  

[气球[颜色=红色地址=地址{州= redState，城市= redCity}]，气球[颜色=颜色地址=地址{州= blueState，城市= blueCity}]，气球[颜色=黄色地址=地址{state = yellowState，city = yellowCity}]，Balloon [color = Green Address = Address {state = greenState，city = greencity}]]，

[Balloon [color = Red Address = Address {state = redState，城市= redCity}]，Balloon [颜色=颜色地址=地址{state = blueState，城市= blueCity}]，Balloon [color = yellow地址=地址{state = yellowState，城市= yellowCity}]]

因此，在上面的输出中，更改列表中气球的颜色也会影响副本。但是添加新元素不会反映在副本中。

有人可以解释吗？

根据luk2302的回答，以下可视化解释了发生的情况：

    list   object  listCopy
     |___  red   ___|
     |___  blue  ___|
     |___ yellow ___|


     list.add(green);
    list  object  listCopy
     |___  red   ___|
     |___  blue  ___|
     |___ yellow ___|
     |___ green 


     list.remove(blue);
    list  object  listCopy
     |___  red   ___|
           blue  ___|
     |___ yellow ___|
     |___ green