dom xml namespace QName xml parsers DocumentBuilder xml parsers DocumentBuilderFactory w3c dom DOMImplementation w3c dom w3c dom w3c dom ElementTraversal elementprinter argv argv.length printusage documentbuilderfactory dbf documentbuilderfactory.newinstance dbf.setnamespaceaware dbf.setexpandentityreferences documentbuilder db dbf.newdocumentbuilder doc db.parse argv domimplementation domimpl doc.getimplementation domimpl.hasfeature doc.getdocumentelement system.err.println ex ex.printstacktrace depth elementtraversal et elementtraversal depth qname e.getnamespaceuri e.getlocalname et.getchildelementcount firstelementchild et.getfirstelementchild firstelementchild firstelementchild depth et.getnextelementsibling printusage system.err.println