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POHow to synchronize a static variable among threads running different instances of a class in Java?
 

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  1. POHow to synchronize a static variable among threads running different instances of a class in Java?
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    <p>I know that using the <code>synchronize</code> keyword before a method brings synchronization to that object. That is, 2 threads running the same instance of the object will be synchronized. </p> <p>However, since the synchronization is at the object level, 2 threads running different instances of the object will not be synchronized. If we have a static variable in a Java class that is called by the method, we would like it to be synchronized across instances of the class. The two instances are running in 2 different threads. </p> <p>Can we achieve synchronization in the following way? </p> <pre><code>public class Test { private static int count = 0; private static final Object lock= new Object(); public synchronized void foo() { synchronized(lock) { count++; } } } </code></pre> <p>Is it true that since we have defined an object <code>lock</code> that is static and we are using the keyword <code>synchronized</code> for that lock, the static variable <code>count</code> is now synchronized across instances of class <code>Test</code>?</p>
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