在代码String s =" abc" +" xyz";中创建了多少个Java字符串对象？ [英] How many Java string objects created in the code String s="abc"+"xyz";?

问题描述

在以下语句中将创建多少个Java字符串对象？

How many Java string objects will be created in the following statement?

String s = "abc" + "xyz"; 

我猜三个？

推荐答案

编译器为每个JVM启动创建1个String，因为编译器可以在编译时确定生成的String，它是 interned 并静态存储在JVM的字符串表。

The compiler creates 1 String per JVM start, because the compiler can determine the resulting String at compile time, it is interned and statically stored in the JVM's String Table.

FYI，如果该语句连接变量（在运行时无法确定），将创建1个字符串，但它也会创建 StringBuilder 。代码将编译为：

FYI, if the statement were concatenating variables (not determinable at runtime), 1 String would be created, but it would create a StringBuilder too. The code would compile to:

new StringBuilder().append(abcVar).append(xyzVar).toString()

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