java code to get all leaf nodes of a xml
try {
final Document doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse("input.xml");
final XPathExpression xpath = XPathFactory.newInstance().newXPath().compile("//*[count(./*) = 0]");
final NodeList nodeList = (NodeList) xpath.evaluate(doc, XPathConstants.NODESET);
for(int i = 0; i < nodeList.getLength(); i++) {
final Element el = (Element) nodeList.item(i);
System.out.println(el.getNodeName());
}
} catch (Exception e) {
e.printStackTrace();
}