// loop through all elements in XML.
if (stream == null) throw new ConfigurationException("Input stream for configuration xml is null!");
Element root = XmlConfigHelper.getDocumentRoot(stream);
XmlConfigurationParser parser = new XmlConfigurationParser();
confCache = parser.parseElement(root);
if (confCache == null) throw new NullPointerException("Null conf cache!!");
Element list = (Element) root.getElementsByTagNameNS("*", "protocol_stacks").item(0);
NodeList stacks = list.getElementsByTagNameNS("*", "stack");