RFR: 8364182: Add jcmd VM.properties command [v2]

[Kieran Farrell]

On Thu, 8 Jan 2026 19:50:08 GMT, Kieran Farrell <kfarrell at openjdk.org> wrote:

>> The goal of this PR is to add a means of exposing security properties at runtime to aid the debugging security related issues/misconfigurations etc. Currently, only initial security properties set at start up can be exposed via the `InitialSecurityProperty` JFR event. 
>> 
>> This patch introduces a new jcmd diagnostic command `VM.properties`, which enables developers to print either the current system properties or security properties of a running Java process via command-line arguments (-system or -security). To avoid clutter within the jcmd command list, the old `VM.system_properties` command is hidden, but not removed so will not break existing usages. The implementation of each is shared to reduce duplication.
>
> Kieran Farrell has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains eight additional commits since the last revision:
> 
>  - Merge remote-tracking branch 'origin/master' into sec_props2
>  - static helper method for both jcmd calls
>  - missing )
>  - working with single arg
>  - updates
>  - update args
>  - two args -not yet tested
>  - initial patch

it seems the ability to hide JCMD commands via DCmdFactory, _hidden has been removed in JDK-8373441, I will search for an alternative method.

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PR Comment: https://git.openjdk.org/jdk/pull/29124#issuecomment-3725657806