Ok, here's the approximate plan:
1) we'll add explicit dependency for slf4j-api in languagetool-core (btw we already have slf4j-api.jar as a transient dependency)
2) we'll add logging implementation dependency (most probably log4j or logback - I'll do a bit more reading on that)
2) we currently have slf4j-nop as a dependency in languagetool-server, languagetool-standalone, and languagetool-commandline to prevent "Failed to load class org.slf4j.impl.StaticLoggerBinder" message - as I understand we can remove slf4j-nop as we'll have real implementation
This logging support will be primarily for development purposes and if there's some default logging backend configuration needed I'll provide that. If we later to decide to use it for production we'll have to look at it separately.
Please let me know if you have any questions or suggestions,