This is the input XML:
get the namespace first
docFactory.setNamespaceAware(true);
StringBuilder nameSpace = new StringBuilder(
doc.getDocumentElement().getPrefix() != null ? doc.getDocumentElement().getPrefix() + ":" : "");
then use nameSpace variable accrodingly
eg:
Node node= doc.getElementsByTagName(nameSpace + "Node1").item(0)
.getFirstChild();