Hello again can I find a complete documentation somewhere describing the “pattern” property of encoder? There are a few examples inside the documentation, but none of them are really exhaustive. I was surprised to see the output of: pattern = "%d{yyyy-MM-dd HH:mm:ss,SSS} [%t] %-5p - (%c) - %m%n" which wasn’t converted by the tools available (from my log4j.properties). Also... while it’s kind of obvious, I couldn’t find a sentence saying “for the Groovy configuration you need ‘groovy-1.8.3.jar’ on your classpath”. The only thing I found was: “GEventEvaluator depends on the Groovy runtime. It was tested with Groovy version 1.7.2. ” (source: http://logback.qos.ch/setup.html ). I may also have missed the page explaining it all, let me know if I did. Thank you for your time! Best regards Andrew Bourgeois