There might be two issues:
- the two versions of an artifact were left in target/. mvn clean would help you.
- something transitively brings another versions of RichFaces - use mvn dependency:tree to discover what's wrong (you can alternatively open pom.xml in JBDS, which has Dependencies explorer)
Thanks for the clues Lukas.
The explicit steps I used with JBDS:
Project | Run as | Maven clean
Project | Maven | Update Project
Project | Run as | Maven install
Expanding the /target tree down to WEB-INF/lib I now see only the most current versions of the jars identified in my pom.xml