RFR: 8353950: Clipboard interaction on Windows is unstable [v3]

[Damon Nguyen]

On Thu, 15 May 2025 16:48:47 GMT, Matthias Bläsing <mblaesing at openjdk.org> wrote:

>> - Introduce a lock into WClipboard that protects the code between
>>   openClipboard/closeClipboard invocations.
>>   The native side does not allow to open the clipboard multiple
>>   times or share the opened clipboard between multiple threads.
>> 
>> - Remove of need to call openClipboard/closeClipboard from
>>   getClipboardFormats by using the win32 call
>>   GetUpdatedClipboardFormats
>> 
>> - Prevent a race-condition by not registering the connection
>>   between java and native side of clipboard multiple time, but
>>   just at construction time.
>
> Matthias Bläsing has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Add crash reproducer as jtreg test

src/java.desktop/share/classes/sun/awt/datatransfer/SunClipboard.java line 208:

> 206: 
> 207:         try {
> 208:             openClipboard(null);

Can you help me understand why this is better? Seems odd that the try/finally block has `closeClipboard` in the finally block but the `openClipboard` was moved out of the try.

src/java.desktop/windows/classes/sun/awt/windows/WClipboard.java line 189:

> 187:             checkChange(formats);
> 188:         } catch (Throwable ex) {
> 189:             System.getLogger(WClipboard.class.getName()).log(Level.WARNING, "Failed to process handleContentsChanged", ex);

I'm not saying not to necessarily change this, but what are we hoping to see with logging this warning here?

test/jdk/java/awt/Clipboard/ConcurrentClipboardAccessTest.java line 29:

> 27:   @summary tests that concurrent access to the clipboard does not crash the JVM
> 28:   @run main ConcurrentClipboardAccessTest
> 29:  */

It has been brought to my attention that this test needs to be headful since we're dealing with clipboard behavior.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24614#discussion_r2114346429
PR Review Comment: https://git.openjdk.org/jdk/pull/24614#discussion_r2114337249
PR Review Comment: https://git.openjdk.org/jdk/pull/24614#discussion_r2114349984