blocks|key|971680|text|监视器是一种控制对对象的并发访问的机制。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|971681|这允许您执行以下操作：|971682|线程1：|971683|public+void+a()
{
++++synchronized(someObject)+{
++++++++//+do+something+(1)
++++}
}|code-block|syntax|javascript|971684|线程2：|971685|public+void+b()
{
++++synchronized(someObject)+{
++++++++//+do+something+else+(2)
++++}
}|971686|这可以防止线程1和线程2同时访问被监视(同步)的部分。其中一个将启动，监视器将阻止另一个在第一个完成之前访问该区域。|971687|它不是一个特殊的物体。它的同步机制放在类层次结构的根目录：java.lang.Object。|offset|length|style|CODE|971688|还有wait和notify方法，它们也将使用对象的监视器在不同线程之间进行通信。|971689|entityMap^0|0|0|0|0|0|0|0|T|G|0|2|4|7|6|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|11|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|12|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|13|8|@]|9|@]|A|$I|J]]|$1|K|3|L|5|6|7|14|8|@]|9|@]|A|$]]|$1|M|3|N|5|H|7|15|8|@]|9|@]|A|$I|J]]|$1|O|3|P|5|6|7|16|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|17|8|@$S|18|T|19|U|V]]|9|@]|A|$]]|$1|W|3|X|5|6|7|1A|8|@$S|1B|T|1C|U|V]|$S|1D|T|1E|U|V]]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1F|8|@]|9|@]|A|$]]]|Z|$]]

A monitor is mechanism to control concurrent access to an object.

This allows you to do:

Thread 1:

<pre><code>public void a()
{
 synchronized(someObject) {
 // do something (1)
 }
}
</code></pre>

Thread 2:

<pre><code>public void b()
{
 synchronized(someObject) {
 // do something else (2)
 }
}
</code></pre>

This prevents Threads 1 and 2 accessing the monitored (synchronized) section at the same time. One will start, and monitor will prevent the other from accessing the region before the first one finishes.

It's not a special object. It's synchronization mechanism placed at class hierarchy root: <code>java.lang.Object</code>.

There are also <code>wait</code> and <code>notify</code> methods that will also use object's monitor to communication among different threads.

blocks|key|1186071|text|Java语言和运行时系统通过使用监视器支持线程同步。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1186072|监视器与特定的数据项(条件变量)相关联，并作为对该数据的锁定。当一个线程持有某个数据项的监视器时，其他线程将被锁定，并且无法检查或修改数据。|1186073|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

The Java language and runtime system support thread synchronization through the use of monitors. 
A monitor is associated with a specific data item (a condition variable) and functions as a lock on that data. When a thread holds the monitor for some data item, other threads are locked out and cannot inspect or modify the data.

blocks|key|971806|text|http://journals.ecs.soton.ac.uk/java/tutorial/java/threads/monitors.html|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|971807|监视器与对象或数据成员相关联，当数据成员或对象进入同步块(临界区)时获得监视器，当数据成员或对象退出时释放监视器。|971808|entityMap|0|LINK|mutability|MUTABLE|url^0|0|20|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@$A|N|B|O|1|P]]|C|$]]|$1|D|3|E|5|6|7|Q|8|@]|9|@]|C|$]]|$1|F|3|-4|5|6|7|R|8|@]|9|@]|C|$]]]|G|$H|$5|I|J|K|C|$L|4]]]]

<a href="http://journals.ecs.soton.ac.uk/java/tutorial/java/threads/monitors.html" rel="nofollow noreferrer">http://journals.ecs.soton.ac.uk/java/tutorial/java/threads/monitors.html</a>

monitor is associate with object or data member, which is acquire when a data member or object is enter is synchronization block(critical section) and release when is exit.

blocks|key|971878|text|监视器是一种同步构造，它允许线程具有互斥和等待(阻塞)特定条件变为真的能力。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|971879|监视器还具有一种机制，用于向其他线程发出其条件已被满足的信号。它是同时拥有锁和等待集的实体。在Java中，任何对象都可以充当监视器。|971880|在Java虚拟机中，每个对象和类在逻辑上都与一个监视器相关联。要实现监视器的互斥功能，需要将锁(有时称为互斥)与每个对象和类相关联。这在操作系统术语中称为信号量，互斥是一个二进制信号量。|971881|For+more+information+check+the+link|offset|length|971882|entityMap|0|LINK|mutability|MUTABLE|url|http://learningsolo.com/monitor-in-java/^0|0|0|0|0|Z|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|T|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|U|8|@]|9|@$H|V|I|W|1|X]]|A|$]]|$1|J|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|K|$L|$5|M|N|O|A|$P|Q]]]]

Monitor is a synchronization construct that allows threads to have both mutual exclusion and the ability to wait (block) for a certain condition to become true.

Monitors also have a mechanism for signaling other threads that their condition has been met. It is an entity that possesses both a lock and a wait set. In Java, any Object can serve as a monitor.

In the Java virtual machine, every object and class is logically associated with a monitor. To implement the mutual exclusion capability of monitors, a lock (sometimes called a mutex) is associated with each object and class. This is called a semaphore in operating systems terms, mutex is a binary semaphore.

<a href="http://learningsolo.com/monitor-in-java/" rel="nofollow noreferrer">For more information check the link</a>

What's a monitor referred to in concurrent programming in Java?

When I read that "every object has associated a monitor" what does it meaning?

Is it a special object?

What's a monitor in Java?

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Java

在Java的并发编程中，监视器指的是什么？当我读到“每个对象都关联了一个监视器”时，它的意思是什么？它是一个特殊的物体吗？

问在Java中什么是监视器？
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