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

[Semyon Sadetsky]

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
>