RFR(s): 8203682: Add jcmd "VM.classloaders" command to print out class loader hierarchy, details

[Bernd Eckenfels]

Anything which can be done with the DelegatingClassLoaders (either add Info on their target or collabs them to a „30 x unnamed DelegatingClassloader“. Even in Verbose mode they only reveal their type (constructor,  method) but not much more.

Gruss
Bernd
--
http://bernd.eckenfels.net
________________________________
From: serviceability-dev <serviceability-dev-bounces at openjdk.java.net> on behalf of Thomas Stüfe <thomas.stuefe at gmail.com>
Sent: Monday, May 28, 2018 6:50:34 AM
To: serviceability-dev at openjdk.java.net serviceability-dev at openjdk.java.net; Hotspot dev runtime
Subject: Re: RFR(s): 8203682: Add jcmd "VM.classloaders" command to print out class loader hierarchy, details

All tests passed on jdk-submit.

Anyone interested in a review?

More output examples for jcmd VM.classloaders :

Spring framework, basic tree:
http://cr.openjdk.java.net/~stuefe/webrevs/8203682-jcmd-print-classloader-hierarchy/example_spring_short.txt

Spring framework, including all classes:
http://cr.openjdk.java.net/~stuefe/webrevs/8203682-jcmd-print-classloader-hierarchy/example_spring_long.txt

... Thomas

On Wed, May 23, 2018 at 2:46 PM, Thomas Stüfe <thomas.stuefe at gmail.com> wrote:
> Dear all,
>
> (not sure if this would be a serviceability or runtime rfe, so sorry
> for crossposting)
>
> may I please have feedback/reviews for this small enhancement.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8203682
> Webrev: http://cr.openjdk.java.net/~stuefe/webrevs/8203682-jcmd-print-classloader-hierarchy/webrev.00/webrev/
>
> This adds a new command to jcmd, "VM.classloaders". It complements the
> existing command "VM.classloader_stats".
>
> This command, in its simplest form, prints the class loader tree. In
> addition to that, it optionally prints out loaded classes (both
> non-anonymous and anonymous) and various classloader specific
> information.
>
> Examples:
>
> http://cr.openjdk.java.net/~stuefe/webrevs/8203682-jcmd-print-classloader-hierarchy/example.txt
> http://cr.openjdk.java.net/~stuefe/webrevs/8203682-jcmd-print-classloader-hierarchy/example-with-classes.txt
> http://cr.openjdk.java.net/~stuefe/webrevs/8203682-jcmd-print-classloader-hierarchy/example-with-reflection-and-noinflation.txt
>
>
> Thanks and Best Regards,
>
> Thomas
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