Graylog2/graylog2-server — pull request #105 by joschi (2012-11-20 22:32:31+00:00)
Title: Consequent SLF4J usage

Replaced the usage of Log4j throughout graylog2-server (2 exceptions to the rule) with SLF4J which has already been a dependency for a long time.

This will make it easier to replace Log4j with [Logback](http://logback.qos.ch/) or [Log4j 2](http://logging.apache.org/log4j/2.x/) in the future.

Also SLF4J supports string interpolation in a way so that `String` objects are only constructed at the actual logging time, which makes calls to e. g. `Logger.isDebugEnabled()` obsolete in most cases.