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Sep 21, 2024
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修改错别字/笔误 #2487

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4 changes: 2 additions & 2 deletions docs/java/concurrent/java-concurrent-questions-02.md
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Expand Up @@ -549,15 +549,15 @@ public class SynchronizedDemo2 {

![synchronized关键字原理](https://oss.javaguide.cn/github/javaguide/synchronized%E5%85%B3%E9%94%AE%E5%AD%97%E5%8E%9F%E7%90%862.png)

`synchronized` 修饰的方法并没有 `monitorenter` 指令和 `monitorexit` 指令，取得代之的确实是 `ACC_SYNCHRONIZED` 标识，该标识指明了该方法是一个同步方法。JVM 通过该 `ACC_SYNCHRONIZED` 访问标志来辨别一个方法是否声明为同步方法，从而执行相应的同步调用。
`synchronized` 修饰的方法并没有 `monitorenter` 指令和 `monitorexit` 指令，取而代之的是 `ACC_SYNCHRONIZED` 标识，该标识指明了该方法是一个同步方法。JVM 通过该 `ACC_SYNCHRONIZED` 访问标志来辨别一个方法是否声明为同步方法，从而执行相应的同步调用。

如果是实例方法，JVM 会尝试获取实例对象的锁。如果是静态方法，JVM 会尝试获取当前 class 的锁。

#### 总结

`synchronized` 同步语句块的实现使用的是 `monitorenter` 和 `monitorexit` 指令，其中 `monitorenter` 指令指向同步代码块的开始位置，`monitorexit` 指令则指明同步代码块的结束位置。

`synchronized` 修饰的方法并没有 `monitorenter` 指令和 `monitorexit` 指令，取得代之的确实是 `ACC_SYNCHRONIZED` 标识，该标识指明了该方法是一个同步方法。
`synchronized` 修饰的方法并没有 `monitorenter` 指令和 `monitorexit` 指令，取而代之的是 `ACC_SYNCHRONIZED` 标识，该标识指明了该方法是一个同步方法。

**不过两者的本质都是对对象监视器 monitor 的获取。**

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