RFR: 8274597: [TESTBUG] Two of the dnd tests times out and fails

[Sergey Bylokhov]

On Thu, 30 Sep 2021 14:24:50 GMT, Manukumar V S <mvs at openjdk.org> wrote:

> These two dnd tests fails most of the time with a time out, mostly noticed in windows 11 machines.
> 1. java/awt/dnd/AcceptDropMultipleTimes/AcceptDropMultipleTimes.java
> 2. java/awt/dnd/DropTargetEnterExitTest/MissedDragExitTest.java
> 
> Fix:
> From the logs, I have noticed that some of the non-daemon threads are still waiting even after the test execution is complete. So it could be possible that java is waiting for these threads to be finished execution before the main thread exits.
> As a fix for this, I have put a Thread.sleep(100) at the end of the main() in order to enable other non-daemon threads get a chance to finish their execution before the main thread completes.

Looks like the hang occurs in some of the hook executed at the "exit" step. DId you check which ShutdownHook is executed and hang? Is it possible it is some of the AWT toolkit related?

	at java.lang.Object.wait(java.base at 11.0.14-ea/Native Method)
	- waiting on <0x00000000ff504d78> (a java.lang.Thread)
	at java.lang.Thread.join(java.base at 11.0.14-ea/Thread.java:1305)
	- waiting to re-lock in wait() <0x00000000ff504d78> (a java.lang.Thread)
	at java.lang.Thread.join(java.base at 11.0.14-ea/Thread.java:1379)
	at java.lang.ApplicationShutdownHooks.runHooks(java.base at 11.0.14-ea/ApplicationShutdownHooks.java:107)
	at java.lang.ApplicationShutdownHooks$1.run(java.base at 11.0.14-ea/ApplicationShutdownHooks.java:46)

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PR: https://git.openjdk.java.net/jdk/pull/5777