I spent half a day trying to figure out why the app on the staging server does not log in the app log file while it does on the dev server.
Server log said log config file found but could not find the root logger.

Problem was that the directory was readable for the app, but not the logfile configuration file.

Dear devs, when a file is not readable that might be some interesting information one could write into a log. AT LEAST MORE INTERESTING THAN "APPLICATION STARTING..."