Re: RFR: 8327246: Add a jcmd diagnostic command to list the jar files loaded by a process [v2]

[David Holmes]

On Tue, 6 Jan 2026 21:29:36 GMT, Larry Cable <d...@openjdk.org> wrote:

>> modified the pre-existing VM.classes jcmd to add a 'location' option, that 
>> when specified, will (natively) attempt to obtain the value (if non-null) of 
>> the location URL of the CodeSource of each classes ProtectionDomain.
>> 
>> effectively:
>> 
>> someObject.getClass().getProtectionDomain().getCodeSource().getLocation().toExternalForm()
>> 
>> (where interim oops are null-checked)
>
> Larry Cable has updated the pull request incrementally with one additional 
> commit since the last revision:
> 
>   JDK-8327246: updated copyright year. fixed Capitialization nit and 
> restructured use of InstanceKlass local as per comments

Overall approach seems reasonable. I have a couple of queries.

Thanks

src/hotspot/share/oops/instanceKlass.cpp line 2359:

> 2357:   // initialization state
> 2358: 
> 2359:   InstanceKlass *ik = k->is_instance_klass() ? InstanceKlass::cast(k) : 
> nullptr;

Suggestion:

  InstanceKlass* ik = k->is_instance_klass() ? InstanceKlass::cast(k) : nullptr;

src/hotspot/share/oops/instanceKlass.cpp line 2386:

> 2384:     oop pd = java_lang_Class::protection_domain(k->java_mirror());
> 2385: 
> 2386:     if (pd != nullptr && (ik = pd->klass()->is_instance_klass() ? 
> InstanceKlass::cast(pd->klass()) : nullptr) != nullptr) {

Is a non-instance-class possible here??

src/hotspot/share/oops/instanceKlass.cpp line 2397:

> 2395:         oop cs = pd->obj_field(csfd.offset());
> 2396: 
> 2397:         if (cs != nullptr && (ik = cs->klass()->is_instance_klass() ? 
> InstanceKlass::cast(cs->klass()) : nullptr) != nullptr) {

Is a non-instance-class possible here??

src/hotspot/share/oops/instanceKlass.cpp line 2406:

> 2404:             oop loc = cs->obj_field(locfd.offset());
> 2405: 
> 2406:             if (loc != nullptr && loc->klass() == 
> vmClasses::String_klass()) {

Why are you checking the class type?

-------------

PR Review: https://git.openjdk.org/jdk/pull/29048#pullrequestreview-3632862000
PR Review Comment: https://git.openjdk.org/jdk/pull/29048#discussion_r2666611656
PR Review Comment: https://git.openjdk.org/jdk/pull/29048#discussion_r2666619018
PR Review Comment: https://git.openjdk.org/jdk/pull/29048#discussion_r2666619778
PR Review Comment: https://git.openjdk.org/jdk/pull/29048#discussion_r2666626257