DefaultConfiguration has unspecified dependency on commons collections

I was going through the guide http://commons.apache.org/proper/commons-configuration/userguide/howto_configurationbuilder.html to parse an xml file and I hit a CNFE on org.apache.commons.collections.CollectionUtils. Maven's dependency for commons-configuration provides no indication that commons collections is needed.

It should either have commons-collections as a dependency or the use of CollectionUtils should be worked around.