Hit AssertionFailureError while running case Thread.Mytester.LotterySchedulerVAR4

[thinkhy]

 /* TestID 3: Test ThreadGrader7 (no ticket transfers (priority donation))        */
    public static void LotterySchedulerVAR4() {                                /*@B4A*/
        System.out.print("++MyTester: enter LotterySchedulerVAR4\n");          /*@B4A*/

        PriopritySchedulerVAR1();                                              /*@B4A*/
        PriopritySchedulerVAR2();                                              /*@B4A*/
        PriopritySchedulerVAR3();                                              /*@B4A*/
        PriopritySchedulerVAR4();                                              /*@B4A*/

        System.out.print("++MyTester: leave LotterySchedulerVAR4\n");          /*@B4A*/
    }

[LotteryQueue.pickNextThread] Sum: 2   LotteryValue: 1
[ThreadState.getEffectivePriority] holder thread: Thread listner (#131) Size: 2
[PriorityQueue.acquire] thread: Thread listner (#131) holder: null
####### runNextThread: nextThread = Thread listner
Switching from: Thread speaker (#130) to: Thread listner (#131)
Running thread: Thread listner (#131)
[PriorityQueue.acquire] thread: Thread listner (#131) holder: nachos.threads.LotteryScheduler$ThreadState@31023102

nachos.machine.AssertionFailureError
        at nachos.machine.Lib.assertTrue(Lib.java:77)
        at nachos.threads.PriorityScheduler$ThreadState.acquire(PriorityScheduler.java:420)
        at nachos.threads.PriorityScheduler$PriorityQueue.acquire(PriorityScheduler.java:173)
        at nachos.threads.Lock.acquire(Lock.java:53)
        at nachos.threads.Condition2.sleep(Condition2.java:48)
        at nachos.threads.Communicator.listen(Communicator.java:86)
        at nachos.threads.Communicator$Listener.run(Communicator.java:130)
        at nachos.threads.KThread.runThread(KThread.java:162)
        at nachos.threads.KThread.access$000(KThread.java:30)
        at nachos.threads.KThread$1.run(KThread.java:150)
        at nachos.machine.TCB.threadroot(TCB.java:240)
        at nachos.machine.TCB.access$100(TCB.java:25)
        at nachos.machine.TCB$1.run(TCB.java:93)
        at java.lang.Thread.run(Thread.java:738)
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