RFR: 8273485: Deadlock when also using Swing and exiting Fullscreen on Mac [v7]

[Florian Kirmaier]

On Mon, 18 Oct 2021 08:20:22 GMT, Florian Kirmaier <fkirmaier at openjdk.org> wrote:

>> When using Swing it's possible to generate a Deadlock.
>>  It's related to the nested eventloop started in enterFullScreenExitingLoop - and the RenderLock aquired when using setView in Scene.
>>  Sample Programm and Threaddump are added to the ticket.
>> 
>> Removing the nested loop fixes the Problem. 
>> I hope this doesn't have any side effect - so far i don't know of any.
>
> Florian Kirmaier has updated the pull request incrementally with one additional commit since the last revision:
> 
>   JDK-8273485
>   Fixing toggle fullscreen!

I've been using macOS 11.6. It is also not so easy for me to test another version.

I guess the exception can easily be "fixed" by checking whether the application is null, in the `Screen.initScreens` method. Should I change it this way?

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PR: https://git.openjdk.java.net/jfx/pull/622