slf4j version conflict while building with Maven

Question

I realised that one of my projects uses slf4j 1.5.8 and Hibernate uses slf4j 1.6. While building with Maven it downloads both jars but I guess the class files of 1.5.8 are u

Answer 1

As you discovered yourself, there are two libraries (Hibernate and some other) transitively importing SLF4J in two different versions. Unfortunately the older version is being picked up by maven (there are some rules which dependency should be chosen by maven in this situation). The solution is to add the exclusion in the dependency that imports older version of SLF4J (com.example:foo-bar is example here):

  com.example
  foo-bar
  1.2.3
   
     
        org.slf4j
        slf4j-api
     
   

If you still experience this problem, issue:

$ mvn dependency:tree

Look for 1.5.8 version and exclude it from all libraries importing it.