#89 Increment and Decrement Problems in Multithreading

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JavaConcurrencyCode Review

What will be printed to the screen? What problems are present? How can they be fixed?

public class Main {
    public static void main(String[] args) {
        final int[] i = {0};

        for (int j = 0; j < 10; j++) {
            for (int c = 0; c < 10; c++) {
                new Thread(() -> {
                    ++i[0];
                    Thread.sleep(3L);
                    --i[0];
                }).start();
            }
        }

        System.out.println(i[0]);
    }
}

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