<Swing Dev> [9] Review Request for 8130735: javax.swing.TimerQueue: timer fires late when another timer starts

[Sergey Bylokhov]

Hi, Semyon.
I see that the chance to reproduce the problem is very very small, 
because we should call addTimer, when we are at lines 171/172. So the 
bug is about really small timings. So the related question: Is it 
possible in the fixed version to call addTimer when we remove 
DelayedTimer from the queue via queue.take(), but before we assign its 
value to the runningTimer?

On 14.07.15 12:51, Alexander Zvegintsev wrote:
> still looks good to me.
>
> Thanks,
>
> Alexander.
>
> On 07/14/2015 12:41 PM, Semyon Sadetsky wrote:
>> Hi Alexander,
>>
>> I added the double check 
>> :http://cr.openjdk.java.net/~ssadetsky/8130735/webrev.01/
>>
>> --Semyon
>>
>> On 7/13/2015 1:24 PM, Alexander Zvegintsev wrote:
>>> Hello Semyon,
>>>
>>> the fix looks good to me.
>>>
>>> P.S. Just a side note, as I can see we could possibly start two 
>>> threads instead of one in startIfNeeded():
>>>
>>>   96     void startIfNeeded() {
>>>   97         if (! running) {
>>>   98             runningLock.lock();
>>>   99             try {
>>>  100                 final ThreadGroup threadGroup = 
>>> AppContext.getAppContext().getThreadGroup();
>>>  101 AccessController.doPrivileged((PrivilegedAction<Object>) () -> {
>>>  102                     String name = "TimerQueue";
>>>  103                     Thread timerThread = new 
>>> ManagedLocalsThread(threadGroup,
>>>  104 this, name);
>>>
>>> !running check is missing after try. It is not the case with current 
>>> code base, but it may be changed in future.
>>>
>>> Thanks,
>>>
>>> Alexander.
>>>
>>> On 07/09/2015 08:08 PM, Semyon Sadetsky wrote:
>>>> Hello,
>>>>
>>>> Please review fix for JDK9:
>>>>
>>>> bug: https://bugs.openjdk.java.net/browse/JDK-8130735
>>>> webrev: http://cr.openjdk.java.net/~ssadetsky/8130735/webrev.00/
>>>>
>>>> The root cause is the setting larger expiration time for the timer 
>>>> which is already inserted into the delay queue. So all timers 
>>>> behind the timer cannot be executed earlier than its expiration 
>>>> time. This happens very rare only for repeated timers and only if 
>>>> user uses the Swing timer API inaccurately (call start() without 
>>>> stop()).
>>>> The fix eliminates this possibility by introducing a check if the 
>>>> timer was already restarted concurrently.
>>>> It is difficult to write test because I could not reliably 
>>>> reproduce the issue for a reasonable time.
>>>>
>>>> --Semyon
>>>
>>
>


-- 
Best regards, Sergey.

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