I am trying to use CompositeConfiguration class from Apache Commons and I'm getting a NoClassDefFoundError for NestableRunTimeException. In my reading on this problem there are a number of references to incompatible dependencies on versions of commons-lang. Unfortunately they all reference versions older than what I have. I am using commons-configuration-1.9.jar and commons-lang3-3.1.jar in my build path. What are the correct versions I should be using? TIA.