Simpler way to exlude commons-logging in Spring

[Ceki Gülcü]

Chapter 1 of the Spring documentation, more precisely section 1.3.2.1, describes a strategy of replacing commons-logging with slf4j. The described strategy uses maven exclusions. I think a considerably simpler and more robust strategy is to declare commons-logging in the provided scope. The actual commons-logging classes would be provided by jcl-over-slf4j. This translates into the following pom file snippet:

<dependency>
<groupId>commons-logging</groupId>
<artifactId>commons-logging</artifactId>
<version>1.1.1</version>
<scope>provided</scope>
</dependency>

<dependency>
<groupId>org.slf4j</groupId>
<artifactId>jcl-over-slf4j</artifactId>
<version>1.6.1</version>
</dependency>

The first dependency declaration essentially states that commons-logging will be "somehow" provided by the user's environment. The second declaration includes jcl-over-slf4j into your project. As jcl-over-slf4j is a perfect binary-compatible replacement for commons-logging, the first assertion becomes true.

This approach covers all dependencies using commons-logging with just one declaration whereas with the explicit exclusion approach commons-logging needs to be explicitly excluded in every dependency depending on common-logging.