On Tue, 16 Dec 2025 20:43:14 GMT, Kevin Walls <[email protected]> wrote:
>> More context: https://openjdk.org/jeps/137 >> >>> 1-1 Overview >>> >>> The diagnostic command framework is fully implemented in native code and >>> relies on HotSpot's internal exception mechanism. The rationale for a pure >>> native implementation is to be able to execute diagnostic commands even in >>> critical situations like an out-of-memory condition. All diagnostic >>> commands are registered in a single list, and two flags control the way a >>> user can interact with them. The hidden flag prevents a diagnostic command >>> from appearing in the list of available commands returned by the help >>> command. However, it's still possible to get the detailed help message for >>> a hidden command with the help <command name> syntax, but it requires >>> knowing the name of the hidden command. The second flag is enabled and it >>> controls whether a command can be invoked or not. When listed with the help >>> commands, disabled commands appear with a [disabled] label in their >>> descriptions. If the user tries to invoke a disabled command, an error >>> message is returned and the command is not run. Th is error message can be customized on a per-command basis. The framework just provides these two flags with their semantics; it doesn't provide any policy or mechanism to set or modify these flags. These actions will be delegated to the JVM or specific diagnostic commands. >> >> The diagnostic command framework was developed at the same time we had >> requests to implement "Commercial features", the "enabled" flag might also >> have been intended to guard those commercial features (gone now). > > Thanks @fparain Frederic for the extra context. Had wondered if this feature > had ever been used, particularly all the mechanism around the possible JMX > Notification. After this change, we may look at whether it should be removed > also. Thanks @kevinjwalls @fparain @kevinjwalls for the review ------------- PR Comment: https://git.openjdk.org/jdk/pull/28794#issuecomment-3662832242
