slf4j is a facade. It does not do much alone. logback / log4j2 are 2 implementations of the slf4j facade. log4j2 is a community driven project and it is mainta

slf4j is a facade. It does not do much alone. logback / log4j2 are 2 implementations of the slf4j facade. log4j2 is a community driven project and it is maintained with Apache License 2.0. It addresses some issues of logback. If you run into this issues in production, you can switch to log4j2, given that you are using slf4j (which is the recommendation). commons-logging is pretty dead, and nobody makes a deal about it. It has not been updated for around 5 yrs. You clearly need to understand the difference between slf4j and logback/log4j2. And you should learn more about what the Apache Software Foundation is doing. I consider it better not to trust a single company when it comes to important things. It has often proven in the past.