Instead to find where org.w3c.dom comes from I've been using this script:
mvn dependency:copy-dependencies -DincludeScope=test -DoutputDirectory=deps
for i in deps/*.jar; do if unzip -l $i| grep -q org.w3c.dom; then echo $i; fi ; done
D. Lewis. SIGIR '92: Proceedings of the 15th annual international ACM SIGIR conference on Research and development in information retrieval, page 37--50. New York, NY, USA, ACM Press, (1992)