RFR: 8362289: [macOS] Remove finalize method in JRSUIControls.java

[Sergey Bylokhov]

On Tue, 15 Jul 2025 20:24:36 GMT, Sergey Bylokhov <serb at openjdk.org> wrote:

>> Eliminate a finalize() method in the Swing macOS implementation.
>> 
>> I tested that the dispose method is being called by running this small test in combination with some 'println' statements in the source code (now removed)
>> 
>> import javax.swing.JTabbedPane;
>> import javax.swing.plaf.TabbedPaneUI;
>> 
>> public class CreateTabbedPaneUIStressTest {
>> 
>>    public static void main(String[] args) {
>>        for (int i=0; i<1000000000; i++) {
>>            JTabbedPane jtp = new JTabbedPane();
>>            TabbedPaneUI tpui = jtp.getUI();
>>        }
>>    }
>> }
>> 
>> 
>> I also monitored the process size using 'top'.
>> And when I commented out the native call that did the free and re-tested I saw process size grow.
>> 
>> Turning the above into a useful regression test doesn't seem possible to me.
>> Limiting Java heap is pointless (and I did use -Xmx20m) since it is a native resource that is to be freed and failure to dispose won't show up as a problem without taking down the machine.
>
> src/java.desktop/macosx/classes/apple/laf/JRSUIControl.java line 115:
> 
>> 113:         flipped = other.flipped;
>> 114:         cfDictionaryPtr = getCFDictionary(flipped);
>> 115:         if (cfDictionaryPtr == 0) throw new RuntimeException("Unable to create native representation");
> 
> Just a side topic to discuss: In the past I tried to look into this pattern and figure out is it possible for the GC to start cleaning the object after we allocate the native resource but before we register it with Disposer.addRecord. In such a case, the cleanup might never be executed.
> 
> Perhaps we should consider adding a reachabilityFence at the end of Disposer.addRecord, for both the DisposerRecord and the referent, to ensure they remain reachable. Similarly how it was done for cleaner:
> https://hg.openjdk.org/jdk9/jdk9/jdk/rev/1f33e517236e
> Or may be we can just use cleaner.

there is even a bug for Cleaner that the reachabilityFence should be moved to the end of register:
https://bugs.openjdk.org/browse/JDK-8291867
If there are no objectiosn I'll add it to the Disposer.addRecord in a separate bug.

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PR Review Comment: https://git.openjdk.org/jdk/pull/26331#discussion_r2208767482