RFR(s): jcmd VM.classloaders should fold similar loaders

[Thomas Stüfe]

Thank you Coleen!


On Wed, Jun 27, 2018 at 5:58 PM,  <coleen.phillimore at oracle.com> wrote:
>
> This change seems fine to me and looks like it makes reading this output a
> lot better.
> Thanks,
> Coleen
>
>
> On 6/22/18 3:10 PM, Thomas Stüfe wrote:
>>
>> Resent with the correct subject, sorry.
>>
>> ..Thomas
>>
>> On Fri, Jun 22, 2018 at 9:08 PM, Thomas Stüfe <thomas.stuefe at gmail.com>
>> wrote:
>>>
>>> Hi all,
>>>
>>> may I have reviews for this small enhancement to the jcmd
>>> VM.classloader diagnostic command:
>>>
>>> https://bugs.openjdk.java.net/browse/JDK-8205531
>>>
>>> http://cr.openjdk.java.net/~stuefe/webrevs/8205531-vm.classloader-tree-folding/webrev.00/webrev/
>>>
>>>
>>> VM.classloaders prints a tree of class loaders. This tree can grow a
>>> lot and become unwieldy, especially with a lot of similar loaders. One
>>> prime example is the DelegatingClassLoader. It would be helpful were
>>> all these loaders:
>>>
>>> 13114:
>>> +-- <bootstrap>
>>>        |
>>>        +-- "platform",
>>> jdk.internal.loader.ClassLoaders$PlatformClassLoader
>>>              |
>>>              +-- "app", jdk.internal.loader.ClassLoaders$AppClassLoader
>>>                    |
>>>                    +-- test3.internals.InMemoryClassLoader
>>>                          |
>>>                          +-- jdk.internal.reflect.DelegatingClassLoader
>>>                          |
>>>                          +-- jdk.internal.reflect.DelegatingClassLoader
>>>                          |
>>>                          +-- jdk.internal.reflect.DelegatingClassLoader
>>>                          |
>>>                          +-- jdk.internal.reflect.DelegatingClassLoader
>>>                          |
>>>                          +-- jdk.internal.reflect.DelegatingClassLoader
>>>                          |
>>>                          ...... repeat 1495 times
>>>
>>>   folded into one:
>>>
>>> 13114:
>>> +-- <bootstrap>
>>>        |
>>>        +-- "platform",
>>> jdk.internal.loader.ClassLoaders$PlatformClassLoader
>>>              |
>>>              +-- "app", jdk.internal.loader.ClassLoaders$AppClassLoader
>>>                    |
>>>                    +-- test3.internals.InMemoryClassLoader
>>>                          |
>>>                          +-- jdk.internal.reflect.DelegatingClassLoader
>>> (+ 1499 more)
>>>
>>>
>>> Original idea by Bernd Eckenfels, see
>>>
>>> http://mail.openjdk.java.net/pipermail/serviceability-dev/2018-May/023824.html
>>>
>>> Thank you, Thomas
>
>