How do I set up commons-logging to use logback?

Question

We use slf4j + logback, and happened to have some third-party libraries which use commons-logging. How do I set it up to use logback?

Answer 1

The answer is to not use commons-logging.jar, since SLF4J was designed to do what commons-logging does but better. As @MahdeTo refers to, you need to use jcl-over-slf4j.jar.

Check out the documentation from the slf4j website on migrating from commons-logging.

Answer 2

I come across this question too, and found out jcl-over-slf4j.jar indeed can solve the problem, I couldn't understand that why commons-logging couldn't use logback automatically, since commons-logging is log interface and logback is implementation, they should integrate automatically, until I found this:

The Apache Commons Logging (JCL) provides a Log interface that is intended to be both light-weight and an independent abstraction of other logging toolkits. It provides the middleware/tooling developer with a simple logging abstraction, that allows the user (application developer) to plug in a specific logging implementation.

JCL provides thin-wrapper Log implementations for other logging tools, including Log4J, Avalon LogKit (the Avalon Framework's logging infrastructure), JDK 1.4, and an implementation of JDK 1.4 logging APIs (JSR-47) for pre-1.4 systems. The interface maps closely to Log4J and LogKit.

Obviously not all the log interface can integrate nicely with log implementation which mean, if you really want to use logback, jcl-over-slf4j.jar is your only solution now because JCL only support Log4J, Logkit, JDK 1.4.

Answer 3

Just add jcl-over-slf4j to the dependencies of your project (check current version at https://search.maven.org/search?q=g:org.slf4j%20AND%20a:jcl-over-slf4j&core=gav)

Answer 4

for those all who wants to keep the final package size smaller; checkout mvn dependency:tree result of your project and if any dependency to commons-logging exists, exclude them as well. Since the jcl-over-slf4j.jar contains both Log and LogFactory classes with exact same package structure, these commons-logging jars will be extra on your final package.