I needed to redirect System.out/err.println outputs to slf4j.
I know that this is not the way to do logging properly but there is an external librar
You can use sysout-over-slf4j.
The sysout-over-slf4j module allows a user to redirect all calls to System.out and System.err to an SLF4J defined logger with the name of the fully qualified class in which the System.out.println (or similar) call was made, at configurable levels.
If you are not using Maven, download the jar and add it to your classpath.
Alternatively, add it as a Maven dependency:
uk.org.lidalia
sysout-over-slf4j
1.0.2
Then at application startup, call:
SysOutOverSLF4J.sendSystemOutAndErrToSLF4J();