Hi, I am using the CombinedConfiguration class to combine two XMLConfigurations and trying to save the result as xml. My code is as follows: CombinedConfiguration cc = new CombinedConfiguration(new OverrideCombiner()); cc.addConfiguration(firstXMLConfig); cc.addConfiguration(secondXMLConfig); combinedConfig = new XMLConfiguration(cc); combinedConfig.save("path/to/file.xml"); When I try to do the save operation however, I am getting the following exception: Caused by: java.lang.ClassCastException: org.apache.commons.configuration.tree.ViewNode cannot be cast to org.apache.commons.configuration.HierarchicalConfiguration$Node at org.apache.commons.configuration.HierarchicalConfiguration$BuilderVisitor.visitBeforeChildren(HierarchicalConfiguration.java:1624) at org.apache.commons.configuration.HierarchicalConfiguration$Node.visit(HierarchicalConfiguration.java:1329) at org.apache.commons.configuration.XMLConfiguration$XMLBuilderVisitor.processDocument(XMLConfiguration.java:1321) at org.apache.commons.configuration.XMLConfiguration.createDocument(XMLConfiguration.java:759) at org.apache.commons.configuration.XMLConfiguration.save(XMLConfiguration.java:878) at org.apache.commons.configuration.AbstractHierarchicalFileConfiguration$FileConfigurationDelegate.save(AbstractHierarchicalFileConfiguration.java:454) at org.apache.commons.configuration.AbstractFileConfiguration.save(AbstractFileConfiguration.java:546) at org.apache.commons.configuration.AbstractFileConfiguration.save(AbstractFileConfiguration.java:513) at org.apache.commons.configuration.AbstractFileConfiguration.save(AbstractFileConfiguration.java:491) at org.apache.commons.configuration.AbstractFileConfiguration.save(AbstractFileConfiguration.java:403) ... 26 more It looks like ViewNode is created when firstXMLConfig and secondXMLConfig have a node with the same key in the combine process. Is there a way to convert all ViewNodes into HierarchicalConfiguration.Node? Or am I using this incorrectly? Thanks, Jonathan