Change in properties for logging: deliberate?

Daniel Fuchs daniel.fuchs at
Fri Nov 10 16:04:29 UTC 2017

Hi Jason,

I have done a few tests with JDK 8 & 7.

I have created custom handlers and added some
debug traces in their constructors and debug methods.

Then I have added these two lines to my

handlers = custom.Handler
.handlers = custom.DotHandler

What I see is this:

- the first time the configuration is read, two handlers
   are added to the root logger:
   - an instance of DotHandler (first), then an instance
     of Handler (second).

Then if you call LogManager.readConfiguration() again,
both handlers are closed, and this time only one
instance of Handler is added to the root logger.
No instance of DotHandler is added.
 From now on the property is ignored.

This is because the root logger is a special beast:
it will not be removed (like all other loggers) when
LogManager.readConfiguration() is called.

And as it happens, handlers are added to loggers
when the loggers are added to the LogManager.
As it happens, the ".handlers" property is only parsed
and read when the root logger is added to the LogManager,
and thus only once.

The "handlers" property on the other hand is parsed
every time LogManager.readConfiguration() is called.

Given that, I suspect we should deprecate the use of
".handlers" for the root logger, as it appears that
it has never worked properly. I could work on a patch
for 10 (possibly backport it to 9 update) to preserve
the strange behavior of 7 & 8, but is it worth it?

What are your thoughts?

best regards,

-- daniel

On 09/11/2017 19:50, Jason Mehrens wrote:
> Daniel,
> I would assume you would fix since it is advertised as a feature over here:
> If it helps, I've dug up a lot of the history on this over here a while back:
> I've updated that to include the links to this new issue.  Now that I've linked this message thread to that message thread that should crash the internet. :)
> Jason
> ________________________________________
> From: core-libs-dev <core-libs-dev-bounces at> on behalf of Daniel Fuchs <daniel.fuchs at>
> Sent: Thursday, November 9, 2017 1:29 PM
> To: mandy chung
> Cc: core-libs-dev at
> Subject: Re: Change in properties for logging: deliberate?
> On 09/11/2017 19:16, mandy chung wrote:
>> Daniel - we should add this known issue in the release note and document
>> the workaround.
> Hi Mandy,
> Right, it either need to be fixed, or documented in the release
> notes. Let me first have a look at the issue though.
> best regards,
> -- daniel

More information about the core-libs-dev mailing list