JMC with Static Portable JRE 11

[Mario Torre]

The API for jdk.management is new, and also all the others were before
accessible through the tools.jar if I recall correctly, since by
default the jre has been replaced with the modular jdk it's possible
our scripts omit some libraries? If I remember correctly Jiri said
that the jre is created "manually", perhaps some of the API that's
supposed to be included isn't and it's only found in the full jvm.

You should be able to check this by grepping for "jdk.management" in
the binary tree and see the difference between the two builds.

Cheers,
Mario


On Wed, Nov 20, 2019 at 7:17 PM Jie Kang <jkang at redhat.com> wrote:
>
> Hey Alex, Mario,
>
> I just wanted to give a quick status update to clarify that I am going
> to get to the bottom of this.
>
> I tried to run JMC with the static JRE 11 build on Linux and got the
> same issue with being unable to see JVMs on the system. JMC on launch
> warns:
>
> WARNING: Unknown module: jdk.management.agent specified to --add-exports
> WARNING: Unknown module: jdk.attach specified to --add-exports
> WARNING: Unknown module: jdk.internal.jvmstat specified to --add-exports
> WARNING: Unknown module: jdk.attach specified to --add-opens
>
> I am assuming these are needed for the JVM discovery mechanism. I will
> see how the static builds are made in openjdk.  Maybe there's an
> alternative API that the JRE 11+ provides that JMC can use instead?
> Otherwise we can conclude that JMC will not have discovery capability
> with JRE 11, similar to before modules were introduced. In this
> situation it can still be used with JRE to open and analyze JFR files
> on disk.
>
>
> Regards,
> Jie Kang
>


--
Mario Torre
Associate Manager, Software Engineering
Red Hat GmbH <https://www.redhat.com>
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