java - 在 Java 中与不可变对象(immutable对象)共享内部结构是什么意思？

Question

我一直在阅读 Effective Java 并且我看到这样的说法:您不仅可以共享不可变对象(immutable对象)，还可以共享它们的内部结构。但是，我正在努力弄清楚这真正的含义，并且示例肯定会有所帮助，因为书中没有给出示例。我已经知道不可变对象(immutable对象)无法更改，例如 String。

Answer 1

阅读book进一步:

The BigInteger class uses a sign-magnitude representation internally. The sign is represented by an int and the magnitude is represented by an int array. The negate method produces a new BigInteger of like magnitude and opposite sign. It does not need to copy the array; the newly created BigInteger points to the same internal array as original.