On Fri, 4 Mar 2022 07:34:35 GMT, Chris Plummer <cjplum...@openjdk.org> wrote:
>> jdb has a probably very little used command called "threadgroup" which is
>> used to set the current TheadGroup. The only purpose of the current
>> ThreadGroup is as the default ThreadGroup to use for the "threads" command
>> when no ThreadGroup argument is passed to it.
>>
>> "threads" prints out every thread in the ThreadGroup specified as the first
>> argument. If none is specified, it uses the current ThreadGroup. If the
>> current ThreadGroup has not yet been specified, it automatically gets set to
>> the top level ThreadGroup.
>>
>> Once the current ThreadGroup has been set by using the threadgroup command,
>> it's not that obvious how to reset it back to the default. It turns out the
>> way to do this to set it to the "system" ThreadGroup, which is the top level
>> ThreadGroup (and therefore the initial current ThreadGroup).
>>
>> With this enhancement I've made it so if you use the "threadgroup" command
>> with no argument, it resets the current ThreadGroup back to the top level
>> ThreadGroup ("system"). Previously with no argument it produces an error for
>> not specifying the ThreadGroup argument.
>
> Chris Plummer has updated the pull request incrementally with two additional
> commits since the last revision:
>
> - Use THREADGROUP_NAME instead of "MyThreadGroup#"
> - fix minor typo in help text
Looks good.
(Choosing the null or top-level thread group means to show all threads in all
thread groups, that makes sense though I didn't find if we say it anywhere. A
niche feature like you say, but good to have a way back from choosing a thread
group!)
-------------
Marked as reviewed by kevinw (Committer).
PR: https://git.openjdk.java.net/jdk/pull/7687
