import java.util.concurrent.Executors;
import java.util.stream.IntStream;
import java.util.concurrent.TimeUnit;

public class MultiThreading {
    private int number = 0;

    public static void main(String[] args) throws InterruptedException {
        final var multiThreading = new MultiThreading();

        final var service = Executors.newFixedThreadPool(3);
        IntStream.range(0, 1000)
            .forEach(count -> service.submit(multiThreading::increment));
        service.awaitTermination(1000, TimeUnit.MILLISECONDS);

        System.out.println(multiThreading.number);
    }

    public synchronized void increment() {
        number += 1;
    }
}