[logback-user] Why is Logback being configured twice?

[Daniel Serodio (lists)]

I'm trying to switch an application from from log4j to Logback. This app 
uses SLF4J, Spring Framework and is deployed in Tomcat 7.

Spring Framework uses JCL, so I added the following JARs to the 
application's classpath:

slf4j-1.6.1.jar
jcl-over-slf4j-1.6.1.jar
logback-classic-0.9.29.jar
logback-core-0.9.29.jar

I created a logback.xml file, with debug="true" so I could debug my 
configuration.

When I deploy this webapp in Tomcat, I can see that Logback is being 
configured twice. Why would this happen?

Thanks in advance,
Daniel Serodio