RFR (L): 8046148: JEP 158 Unified JVM Logging

Claes Redestad claes.redestad at oracle.com
Tue Sep 8 11:42:52 UTC 2015

On 2015-09-08 12:45, Kirk Pepperdine wrote:
> Hi,
> Indeed, not all messages are hierarchical. This is one of the reasons I originally questioned the use of log levels. For example, debugging and informational logs may come from the same source and I certainly wouldn’t want to be forced mix them to satisfy a forced structure. Is the intention you can use either or? I ask because I’m not sure that mixing them with tags will alleviate the problems I commonly see when tuning applications in the field.
>> Log levels have always been part of the plan as far as I can tell. Both the first and second proposal include the levels in their descriptions. In any case, the JEP is due for integration and it is too late for such a fundamental change to the feature now.
> I would like to believe that this work is important enough to get right and that it’s never too late for fundamental changes up until it is integrated. I would like to believe that there are back out strategies in the cases where implementations show unintended consequences.

Can you give an example of what you believe will go wrong with allowing 
a mix of levels and tags and how removing levels from the JEP would 
improve things?

Having high-level tags which interact with the standard "levels" seem 
like a natural fit to me, while the framework proposed in the JEP make 
it possible for each VM team to support ever more detailed tags to each 
subsystem where that might be appropriate. For better or worse it adds a 
degree of freedom. Is your concern that we need more granular tags going 
forward to help zooming in on specific issues, and that levels for such 
niche tags might seem/feel superfluous?



> Kind regards,
> Kirk Pepperdine

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