RFR: 8255248: NullPointerException in JFXPanel due to race condition in HostContainer [v8]

[Kevin Rushforth]

On Wed, 19 Nov 2025 16:30:01 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 one additional commit since the last revision:
> 
>   Review comment

Looks good with one more minor suggestion. As mentioned offline, we'll do a CI headful test run.

modules/javafx.graphics/src/main/java/com/sun/javafx/tk/quantum/GlassScene.java line 254:

> 252:         // should only be called on the event thread
> 253:         if (getSceneState() != null) {
> 254:             sceneState.update();

Suggestion:

        if (sceneState != null) {
            sceneState.update();


Minor: it seems cleaner to access `sceneState` directly in both the test and usage rather than mixing them.

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PR Review: https://git.openjdk.org/jfx/pull/1968#pullrequestreview-3483801411
PR Review Comment: https://git.openjdk.org/jfx/pull/1968#discussion_r2542835636