RFR: 8255248: NullPointerException in JFXPanel due to race condition in HostContainer [v11]

[Andy Goryachev]

On Thu, 20 Nov 2025 12:05:37 GMT, Prasanta Sadhukhan <psadhukhan at openjdk.org> wrote:

>> NPE is seen while accessing transient "scenePeer" variable between reads..
>> Fix is made to store it in a temp variable rather than reading it twice since the value can change between successive reads in many places it is accessed.
>> Also some debug logs added to be enabled via `jfxpanel.debug` property
>
> Prasanta Sadhukhan has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Rename var w.r.t the accessing thread for easy perusal
>  - comment fix

Looks good.  Thank you for all the work!

tests/system/src/test/java/test/javafx/embed/swing/JFXPanelNPETest.java line 51:

> 49: import test.util.Util;
> 50: 
> 51: @Timeout(value=30000, unit=TimeUnit.MILLISECONDS)

just FYI: the default time unit is SECONDS, so we can simply write
`@Timeout(30)`

(we used MILLISECONDS earlier to minimize the changes going from junit4)

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Marked as reviewed by angorya (Reviewer).

PR Review: https://git.openjdk.org/jfx/pull/1968#pullrequestreview-3488489554
PR Review Comment: https://git.openjdk.org/jfx/pull/1968#discussion_r2546542092