Querying with XPath

Document response;
// Initialize response object by parsing request...
String query = "/methodResponse/params/param/value/double";
if (impl.hasFeature("XPath", "3.0")) {
  XPathEvaluator evaluator = (XPathEvaluator) response;
  try {
    XPathResult index = evaluator.evaluate(query, response, 
     null, XPathResult.ORDERED_NODE_ITERATOR_TYPE, null)
    // work with the result...
  }
  catch (XPathException ex) {
    System.err.println(query 
     + " is not a correct XPath expression");
  }
  catch (DOMException ex) {
    System.err.println(ex);
  }
}