Started testing Java9 with log4j 1.2, SLF4J and logback projects

Ceki Gülcü ceki at
Tue Feb 14 21:57:44 UTC 2017

Hi Dalibor,

Thank you for the useful pointer to a possible workaround.

The issue impacting the slf4j-log4j12 module (which relies on log4j 
1.2.17) is now fixed. The fix will ship with release 1.7.23 of SLF4J.

See also


On 2/14/2017 17:42, dalibor topic wrote:
> On 14.02.2017 12:14, Ceki Gülcü wrote:
>> In the context of SLF4J, the build of the slf4j-log4j12 module fails
>> since log4j can no longer correctly detect the version of Java and shuts
>> down MDC support. In short, the changes introduced in JEP 223 have
>> significant consequences for log4j 1.2.x and by ricochet for SLF4J.
> Hi Ceki,
> general information about Log4J 1.x on JDK9 can be found at
> .
> In particular, the blog points to a potential workaround for Log4j 1.x,
> although, of course, migrating off libraries that are no longer
> maintained should be the preferred choice for most developers.
> cheers,
> dalibor topic

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