这些指令大多数是为了检查i的初始化，以及使用锁执行线程安全的初始化。

Most of these instructions are in place to check for the initialization of I, and to perform a thread-safe initialization using a lock.

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Node 声称它绝不会死锁，因为它根本不允许使用锁，它不会直接阻塞 I/O 调用。

Node also claims that it will never deadlock, since there are no locks allowed, and it doesn't directly block for I/O calls.

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很多并发性专家事实上往往引导用户远离volatile变量，因为使用它们要比使用锁更加容易出错。

Many concurrency experts tend to guide users away from using volatile variables at all, because they are harder to use correctly than locks.

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