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#436 Problems with parallelStream and a Non-Thread-Safe Collection

Companies:
Alfa-Bank
Themes:
JavaConcurrencyCode Review

What will be printed, and what problems may occur? 

public final class Main {

    public static void main(String[] args) {
        Set<String> threads = new HashSet<>();

        var integers = IntStream.range(0, 7000).boxed().collect(Collectors.toList());
        integers.stream().parallel().forEach(v -> threads.add(Thread.currentThread().getName());

        System.out.println(threads.size());

        //System.out.println(threads);
    }
}

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