Normal int, volatile int, and AtomicInteger thread safety comparison

scratch.java

import java.util.concurrent.atomic.AtomicInteger;

public class scratch extends Thread {

    public static int x = 0;
    public static volatile int y = 0;
    public static AtomicInteger z = new AtomicInteger(0);

    public static void main(String[] args) {
        for (int i = 0; i < 1000; i++) {
            new scratch().start();
        }
        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.printf("x: %d\ny: %d\nz: %d", x, y, z.get());
    }

    @Override
    public void run() {
        for (int i = 0; i < 10000; i++) {
            x++;
            y++;
            z.incrementAndGet();
        }
    }
}