I solved the problem.
For future reference: Remove the <param name="Target" value="System.out" />
from your log4j appender. It does not write to std.out afterwards, but it does start just fine. Maybe its time to migrate to log4j2, so maybe this problem does not exist in log4j2.
The final appender:
<appender name="console" class="org.apache.log4j.ConsoleAppender">
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%-5p %c{1} - %m%n" />
</layout>
</appender>