[RFC][Icedtea-Web]: Fix bug where you can clear cache while plugin is in use.

[Omair Majid]

On 03/15/2011 04:29 PM, Andrew Su wrote:
> Hello Denis,
>
> ----- Original Message -----
>> Hi.
>>
>>>>> - Is it possible to get a race condition when calling
>>>>> markNetxRunning in JNLPRuntime. Since this now affects the
>>>>> plugin and not just javaws, this might be called multiple
>>>>> times by different threads? if so, I would synchronize it and
>>>>> since subsequent calls will instantly return if the first
>>>>> call succeeded in getting the lock, so there won't be much
>>>>> performance hit.
>>
>> I think that's a very good idea (making markNetxRunning
>> synchronized). I don't think we need to worry about performance at
>> all, seeing how rarely this function is called.
>
> It does get called every time it is about to launch an
> applet/application. but as a counter measure it will return right
> away if we obtained the lock already.
>

Without appropriate synchronization, another thread may not see that
it's null already. Being a shared variable that's being read and set by
multiple threads, it needs appropriate synchronization.

Take a look at 
http://download.oracle.com/javase/tutorial/essential/concurrency/memconsist.html

Cheers,
Omair