RFR: 8249627: Degrade Thread.suspend and Thread.resume

[Jaikiran Pai]

On Sun, 18 Sep 2022 16:32:31 GMT, Alan Bateman <alanb at openjdk.org> wrote:

> Degrade Thread.suspend/resume to throw UOE unconditionally.
> 
> Another step in the removal of this deadlock prone mis-feature from the user-facing API. Thread.suspend/resume have been deprecated since JDK 1.2 (1998) and terminally deprecated since Java 14. ThreadGroup.suspend/resume were degraded to throw UOE in Java 19. As of Java 19, Thread.suspend/resume continues to work for platform threads but throws UOE for virtual threads. The next step is to degrade both methods to throw UOE for all threads. A corpus search of 19M classes in 113k JAR files found only 22 classes using these methods so this change is unlikely to be disruptive.
> 
> The change requires some minor adjustments to the JVM TI and JDWP specifications, and a minor update to the JDI docs.
> 
> Leonid Mesnik is working on [PR10351](https://github.com/openjdk/jdk/pull/10351) to remove/replace the last few usages of Thread.suspend/resume from the hotspot tests (most of these can use JVMTI SuspendThread/ResumeThread).

Hello Alan, this PR deletes the `CountStackFrames.java` test case. Is that intentional? Looking at that test case it doesn't have any `suspend`/`resume` related testing and instead is just verifying that `Thread.countStackFrames()` throws the expected `UnsupportedOperationException`.

Edit: Please ignore what I said - I now see that these tests have been moved to a new test file.

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PR: https://git.openjdk.org/jdk/pull/10324