On Mon, 25 Nov 2024 22:34:46 GMT, Jeremy <d...@openjdk.org> wrote:
>> The AWTEventMulticaster is a tree node with 2 children. This PR proposes
>> rebalancing that tree after 500 additions to avoid potential
>> StackOverflowErrors when trying to interact with a large AWTEventMulticaster.
>>
>> In the original headful test:
>> We added 8,000 checkboxes, and when their parent panel was hidden the stack
>> needed to grow to 24,000 lines. It took 8,000 lines to recursively call
>> `java.awt.AWTEventMulticaster.componentHidden`, and then 16,000 additional
>> lines to call two recursive methods to remove a listener:
>>
>> java.desktop/java.awt.AWTEventMulticaster.removeInternal()
>> java.desktop/java.awt.AWTEventMulticaster.remove()
>>
>>
>> With this current PR the max stack size reaches 1,267 instead. (If we
>> rebalanced at EVERY addition, then that same scenario would reach a max
>> stack size of 71.)
>>
>> JDK-8342782 included a headful test case, but I think the main problem it
>> demonstrated can be represented by the headless test case attached to this
>> PR.
>>
>> Depending on how this PR is received I may submit a separate ticket & PR to
>> modify AquaButtonUI so it doesn't always attach an AncestorListener. (That
>> is: if my GUI includes 8,000 checkboxes then I don't need 8,000
>> AncestorListeners.) But JDK-8342782's test case is currently written in a
>> way that should reproduce across all L&F's, so that can be discussed
>> separately.
>
> Jeremy has updated the pull request incrementally with one additional commit
> since the last revision:
>
> 8342782: expanding wildcard imports
>
> This is in response to:
> https://github.com/openjdk/jdk/pull/21962#discussion_r1857389973
src/java.desktop/share/classes/java/awt/AWTEventMulticaster.java line 1020:
> 1018: return new AWTEventMulticaster(array[index0],
> array[index1]);
> 1019: }
> 1020: int mid = (index0 + index1)/2;
Suggestion:
int mid = (index0 + index1) / 2;
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/21962#discussion_r1871376542
