log4j multirelease warning fix for java >= 11

[Hufschmidt]

The log4j fix introduced an anoying warning message when using java version 11 or above everytime the ilServer.jar is invoked: WARNING: sun.reflect.Reflection.getCallerClass is not supported. This will impact performance.

While this is not actually a performance issue and not an issue for the ilServer process itself, it it rather anoying for health- and performance-monitoring scripts.

For example checking current status with: /usr/bin/java -jar '/srv/www/ilias/Services/WebServices/RPC/lib/ilServer.jar' '/var/lib/lucene/ilServer.ini' status

Or when you want to monitor ilServer response-time and answer content locally via cli: /usr/bin/java -jar /srv/www/ilias/Services/WebServices/RPC/lib/ilServer.jar /var/lib/lucene/ilServer.ini search CLIENTID_NID 'Test'.

In both cases a warning message will be send to stdout not even stderr stream, so there is no easy way to filter it out...

By enabling Multi-Release in the ant-build, newer Java version do not complain about this anymore, see:

• https://stackoverflow.com/questions/53049346/is-log4j2-compatible-with-java-11
• https://www.baeldung.com/java-multi-release-jar

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Related Mantis-Ticket: https://mantis.ilias.de/view.php?id=34806