On Thu, 10 Sep 2026 13:08:11 GMT, Kieran Farrell <[email protected]> wrote:
>> This patch adds a new jcmd diagnostic command, `VM.show_settings`, to make >> the existing -`XshowSettings` output available from a running VM. The >> command accepts the same sections as`XshowSettings` (all, vm, properties, >> locale, security, system, security:all, security:properties, >> security:providers, security:tls). >> >> HotSpot registers the new diagnostic command, validates the requested >> section, then calls into `sun.launcher.LauncherHelper` to reuse the existing >> show settings formatting and return the result as bytes for the jcmd stream. >> The VM settings path also passes hotspots `InitialHeapSize`, `MaxHeapSize`, >> and Java thread stack size into the Java helper. A new jcmd test covers VM, >> properties, security TLS, and invalid-input output. >> >> --------- >> - [x] I confirm that I make this contribution in accordance with the >> [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). > > Kieran Farrell has updated the pull request with a new target base due to a > merge or a rebase. The pull request now contains 12 commits: > > - Merge master > - refactor > - split to internal method > - revert mistaken change > - add comment and update print_properties to use CHECK > - remove validation > - extend test coverage and code clean up > - updates > - clean up and add test > - synthax alignmnet > - ... and 2 more: https://git.openjdk.org/jdk/compare/010428f5...f29804f0 Good to see this functionality being offered via jcmd. One thought that occurred while reviewing this PR. Originally, this code was only ever invoked while JVM is launching. It displays initial/launch time configuration. Now, this code can be invoked on demand. The output can be useful and verbose but is it clear that the configuration data dumped is from the initial property maps captured ? I suspect we want users to trigger this command for data not available from other jcmd commands. i.e. for current system properties, use `jcmd <pid> VM.system_properties` , for current security properties, use `jcmd <pid> VM.security_properties` is there a case for displaying initial security and system property data ? Perhaps, and if so, maybe we make it clear that it could be stale data. ------------- PR Comment: https://git.openjdk.org/jdk/pull/31742#issuecomment-5683017984
