The question has been posted before but no real example was provided that works. So Brian mentions that under certain conditions the AssertionError can occur in the followin
Your program is not properly synchronized, as that term is defined by the Java Memory Model.
That does not, however, mean that any particular run will exhibit the assertion failure you are looking for, nor that you necessarily can expect ever to see that failure. It may be that your particular VM just happens to handle that particular program in a way that turns out never to expose that synchronization failure. Or it may turn out the although susceptible to failure, the likelihood is remote.
And no, your test does not provide any justification for writing code that fails to be properly synchronized in this particular way. You cannot generalize from these observations.