Thread Safety with Static Arrays

Question

Consider the `StaticArray` class provided below. What is the primary thread-safety issue demonstrated by this code?

```java
public class StaticArray {
    private static int[] values = new int[3];
    
    public static void increaseAll() {
        for (int i = 0; i < values.length; i++) {
            values[i]++;
        }
    }
    
    public static void main(String[] args) {
        Thread t1 = new Thread(() -> StaticArray.increaseAll());
        Thread t2 = new Thread(() -> StaticArray.increaseAll());
        t1.start();
        t2.start();
    }
}
```

Accepted Answer

The static method increaseAll does not use any synchronization, leading to race conditions when multiple threads modify the static array concurrently.

Answer

Static arrays in Java are immutable by default, so no race condition exists.

Answer

The code is safe because both threads modify the same array in a static context without conflict.

Answer

The use of static prevents the need for instance-level synchronization, which automatically ensures thread safety.

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