Vaadin 7, Liferay 6.2 and logging

Ive been trying to get my vaadin portlets to output anything to its own logfiles, liferays or tomcats logfiles, but i just cant get it to work. Ive been looking around a lot of guides how to enable logging, but i just cant get it to work.

Every guide I find is in some form incomplete, example:

https://vaadin.com/book/vaadin7/-/page/advanced.logging.html

They write: "The basic way to go about this is to add the SLF4J JAR file as well as the jul-to-slf4j.jar file, which implements the bridge from java.util.logging, to SLF4J. "

Well there is not one “SLF4j.JAR” file but there are 25 .jar files in the .zip file you download from http://www.slf4j.org/

So its all a bit of quesswork, and none of my guesses have been right yet…

Any help would be really appreciated, maybe an empty liferay vaadin project with the files needed for logging with working configurations in them?

EDIT: i can get lof4j to log things from my portlet, using this guide:
https://www.liferay.com/web/brett.swaim/blog/-/blogs/using-log4j-to-ensure-each-portlet-has-it-s-own-log-file.
However, my portlet still crashes and the reasons for those crashes do not appear anywhere… So help still needed.