import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.Semaphore;

public class Main {
    private static final List<Integer> productCodeDetailsList = new CopyOnWriteArrayList<>();
    private static final Semaphore semaphore = new Semaphore(1);

    public static void main(String[] args) {
        for (int i = 0; i < 1000; i++) {
            int finalI = i;
            new Thread(() -> {
                try {
                    semaphore.acquire();
                    productCodeDetailsList.add(finalI);
                    if (finalI % 100 == 0) {
                        productCodeDetailsList.clear();
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                } finally {
                    semaphore.release();
                }
            }).start();
        }

        try {
            Thread.sleep(3000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println(productCodeDetailsList);
        System.out.println(productCodeDetailsList.size());
    }
}