The Volatile Keyword in Multithreading

Question

What role does the volatile keyword play for the 'running' flag in this program?
 
```java
public class VolatileFlag {
    private volatile boolean running = true;
    
    public void stop() { 
        running = false;
    }
    
    public void runTask() {
        while(running) {
            // perform some task
        }
        System.out.println("Stopped");
    }
    
    public static void main(String[] args) throws InterruptedException {
        VolatileFlag vf = new VolatileFlag();
        Thread t = new Thread(() -> vf.runTask());
        t.start();
        Thread.sleep(100);
        vf.stop();
    }
}
```

Accepted Answer

It ensures that changes made to the 'running' flag in one thread are immediately visible to the other thread, preventing an infinite loop.

Answer

It optimizes the loop by allowing swift iteration without memory overhead.

Answer

It guarantees atomic execution of the stop() method without the need for additional synchronization.

Answer

It synchronizes the access to the runTask() method, ensuring mutual exclusion.

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