/**
* Initialize XML elements
*/
private void initializeXMLElements() throws DiagnosticException {
try {
xmlHelper = new DomainXMLHelper(repositoryDir);
Element element = xmlHelper.getElement("server", instanceName);
configName = xmlHelper.getAttribute(element, "config-ref");
configElement = xmlHelper.getElement("config", configName);
diagnosticElement = xmlHelper.getElement(configElement,
"diagnostic-service");