Shared Array Modification in Threads

Question

What concurrency-related problem is most likely in this code snippet?
 
```java
public class ConcurrentSum {
    private int[] numbers = {1, 2, 3, 4, 5};

public void computeSum() {
        int sum = 0;
        for (int num : numbers) {
            sum += num;
            numbers[0] = 0; // modifying the array during iteration
        }
        System.out.println(sum);
    }
    
    public static void main(String[] args) {
        ConcurrentSum cs = new ConcurrentSum();
        Thread t1 = new Thread(() -> cs.computeSum());
        Thread t2 = new Thread(() -> cs.computeSum());
        t1.start();
        t2.start();
    }
}
```

Accepted Answer

The concurrent modification of the array during iteration can lead to unpredictable behavior or logical errors.

Answer

Assigning to the first element during iteration will certainly raise an ArrayIndexOutOfBoundsException.

Answer

The computeSum method is thread-safe because the local variable sum is confined to each thread.

Answer

Enhanced-for loops automatically synchronize access to arrays, so no issue arises.

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