++ 运算符线程安全否？

public class TestThread implements Runnable {
    public static int count = 0;
    @Override
    public void run() {
        for (int i = 0; i < 100_0000; i++) {
            count ++;
        }
        System.out.println("end...");
    }
    public static void main(String[] args) throws InterruptedException {
        Runnable runnable = new TestThread();
        for (int i = 0; i < 10; i++) {
            Thread thread = new Thread(runnable);
            thread.start();
        }
        Thread.sleep(60000);
        System.out.println(TestThread.count);
    }
}

end...
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