内存中将创建多少个字符串对象？ [英] How many string objects will be created in memory?

问题描述

以下代码将创建多少个字符串对象？

How many string objects will be created by the following code?

String s="";
s+=new String("a");
s+="b";

我在考试中遇到了这个问题。我想知道正确的答案。我说了2个对象。

池中包含，b的对象和新String（a）创建的对象;

I had this question at exam. I want to know the right answer . I said 2 objects.
The object from pool that contains "" , "b" and the object created by new String("a");

推荐答案

我将回答另一个更清晰的问题：以下代码片段中涉及多少个String实例：

I'll anwser to another, clearer question: how many String instances are involved in the following code snippet:

String s="";
s+=new String("a");
s+="b";

答案是6：

• 空字符串文字：;


• 字符串文字a ;


• 字符串文字a的副本： new String（a） ;


• 通过连接 s 创建的字符串和a;


• 字符串文字b


• 通过连接<$创建的字符串c $ c> s 和b。

• the empty String literal: "";
• the String literal "a";
• the copy of the String literal "a": new String("a");
• the String created by concatenating s and the copy of "a";
• the String literal "b"
• the String created by concatenating s and "b".

如果您假设已经由先前加载的代码创建了三个字符串文字，则代码段会创建3个新的String实例。

If you assume that the three String literals have already been created by previously-loaded code, the code snippet thus creates 3 new String instances.

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