RFR: 8375561: Class NGGroup is in need of some cleanup [v4]

[Andy Goryachev]

On Thu, 22 Jan 2026 17:04:26 GMT, Christopher Schnick <duke at openjdk.org> wrote:

>> This should improve the code quality of the class while preserving its original workings
>
> Christopher Schnick has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Remove unused imports

modules/javafx.graphics/src/main/java/com/sun/javafx/sg/prism/NGGroup.java line 218:

> 216:         for (int i = (startPos == -1 ? 0 : startPos); i < orderedChildren.size(); i++) {
> 217:             NGNode child = orderedChildren.get(i);
> 218:             child.render(g);

more on the concurrency here: if one would instrument the get(int) method in `children`  like so


    private final List<NGNode> children = new ArrayList<>(1) {
        public NGNode get(int ix) {
            System.out.println(Thread.currentThread());
            return super.get(ix);
        }
    };


the log will show accesses from two threads:


Thread[#33,JavaFX Application Thread,5,main]
...
Thread[#28,QuantumRenderer-0,5,main]
...
Thread[#33,JavaFX Application Thread,5,main]


The access pattern for `viewOrderChildren` seem to show only QuantumRenderer thread, though I did not test extensively.

Does anyone know if these two threads are allowed to run in parallel, or is there a mechanism in place that ensures mutual exclusion?

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PR Review Comment: https://git.openjdk.org/jfx/pull/2043#discussion_r2728325064