RFR: 8375561: Class NGGroup is in need of some cleanup [v2]

[Andy Goryachev]

On Fri, 16 Jan 2026 22:47:54 GMT, Michael Strauß <mstrauss at openjdk.org> wrote:

>> modules/javafx.graphics/src/main/java/com/sun/javafx/sg/prism/NGGroup.java line 265:
>> 
>>> 263:                     child = null;
>>> 264:                 }
>>> 265:                 // minimal protection against concurrent update of the list.
>> 
>> see, this is a worrisome comment - and perhaps the value of this PR would be much higher if you can demonstrate that the concurrency is not an issue.
>
> I think that bar is too high, how would you even begin to demonstrate that it _isn't_ an issue? This class iterates over the very same list in six different places, none of which are "protected" with a try-catch block. I would think that this fact should be enough to say that even if concurrent modification was an issue, it must be solved differently.

assuming for a moment that there is a problem (I don't know), at a minimum one needs to check if multiple threads are accessing the list.  the reason is that we might have created a regression:

before - an exception was silently ignored
after - an exception would bubble up and break something else

this is more of an argument against frivolous changes.

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PR Review Comment: https://git.openjdk.org/jfx/pull/2043#discussion_r2700294128