RFR: 8350786: Some java/lang jtreg tests miss requires vm.hasJFR

[Matthias Baesken]

On Thu, 27 Feb 2025 08:49:43 GMT, Alan Bateman <alanb at openjdk.org> wrote:

>> A minimal JVM (**--with-jvm-features=minimal --with-jvm-variants=minimal**) is tested.  This contains no JFR in Hotspot.
>> If you configure the build without JVM feature JFR (like minimal) ,  the tests need the correct requires tags; most tests have this but some not.
>
> If the only VM to be built is the minimal VM then maybe it should filter down the set of modules to include. Just saying that it's a bit strange to include the `jdk.jfr` module but not support JFR, if you see what I mean.
> 
> BTW: I don't object to the change, it's just means that any test using the JFR APIs has to say so twice.

when I list the modules of the  minimal JVM I see a number of modules that will most likely not work because the related JVM features are not present 


images/jdk/bin/java --list-modules
 ...
jdk.jdi at 25.0.0.1-internal
jdk.jdwp.agent at 25.0.0.1-internal
 ...
jdk.jfr at 25.0.0.1-internal
jdk.management at 25.0.0.1-internal
jdk.management.agent at 25.0.0.1-internal
jdk.management.jfr at 25.0.0.1-internal


The minimal JVM does not  contain e.g. JFR, JVMTI or management  JVM features. So most likely those modules miss basic functionality and will not or not fully work.
But fixing this is most likely out of scope of this PR .
Is there some JVM feature to module  mapping and tool support already, I am not aware of it ? 
Would be nice to have this, because removing unneeded (and not working) modules from the image is probably a good idea.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23805#discussion_r1973177693