JCStress在Singleton测试失败

Question

我已经在Singleton上运行了JCStess测试。下面是我的代码。 通常，此代码将因多个线程争夺实例而失败，因为if块将返回多个实例。 但是我的JCStress测试始终成功。

我的考试有什么问题吗？

@Outcome(id = {"2"}, expect = Expect.ACCEPTABLE, desc = "Abnormal outcome")
@Outcome(expect = Expect.FORBIDDEN, desc = "Other forbidden outcome")
@State
public class ConcurrencyTest {

    static class Singleton{

        private static Singleton instance;

        public static volatile int i = 1;

        private Singleton() {
            synchronized (Singleton.class) {
                i++;
            }
        }


        public static Singleton getInstance() {
            if (instance == null) {
                instance = new Singleton();
            }
            return instance;
        }
    }
    @Actor
    public void method1(IntResult1 r) {
        r.r1 = Singleton.getInstance().i;
    }
    @Actor
    public void method2(IntResult1 r) {
        r.r1 = Singleton.getInstance().i;
    }
}