Using log4j2 with slf4j: java.lang.StackOverflowError
You're creating a call-loop with log4j-slf4j-impl-2.3.jar and log4j-to-slf4j-2.3.jar.
log4j-slf4j-impl-2.3.jar is the implementation of the adapter that sends slf4j calls to log4j.
log4j-to-slf4j-2.3.jar is sending log4j calls right back to slf4j. Remove this one.
Just in case, if you have logback in your classpath, it must be removed as well!