I have the following code and have had some trouble with a specific field and it's output. The namespace is connected but doesn't seem to be outputting on the required field. Any info on this would be great.

import org.w3c.dom.Document;
import org.xml.sax.SAXException;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPathFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathExpressionException;
import java.io.ByteArrayInputStream;
import java.io.IOException;

public class test
{
 public static void main(String args[])

 {


     String xmlStr =    "<aws:UrlInfoResponse xmlns:aws=\"http://alexa.amazonaws.com/doc/2005-10-05/\">\n" +
                "    <aws:Response xmlns:aws=\"http://awis.amazonaws.com/doc/2005-07-11\">\n" +
                "        <aws:OperationRequest>\n" +
                "            <aws:RequestId>blah</aws:RequestId>\n" +
                "        </aws:OperationRequest>\n" +
                "        <aws:UrlInfoResult>\n" +
                "            <aws:Alexa>\n" +
                "                <aws:TrafficData>\n" +
                "                    <aws:DataUrl type=\"canonical\">harvard.edu/</aws:DataUrl>\n" +
                "                    <aws:Rank>1635</aws:Rank>\n" +
                "                </aws:TrafficData>\n" +
                "            </aws:Alexa>\n" +
                "        </aws:UrlInfoResult>\n" +
                "        <aws:ResponseStatus xmlns:aws=\"http://alexa.amazonaws.com/doc/2005-10-05/\">\n" +
                "            <aws:StatusCode>Success</aws:StatusCode>\n" +
                "        </aws:ResponseStatus>\n" +
                "    </aws:Response>\n" +
                "</aws:UrlInfoResponse>";

                    DocumentBuilderFactory xmlFact = DocumentBuilderFactory.newInstance();

                    xmlFact.setNamespaceAware(true);

        DocumentBuilder builder = null;
        try {
            builder = xmlFact.newDocumentBuilder();
        } catch (ParserConfigurationException e) {
            e.printStackTrace();       }

        Document doc = null;
        try {
            doc = builder.parse(

     new ByteArrayInputStream( xmlStr.getBytes()));
        } catch (SAXException e) {
            e.printStackTrace();     } catch (IOException e) {
            e.printStackTrace();       }






     System.out.println(doc.getDocumentElement().getNamespaceURI());
     System.out.println(xmlFact.isNamespaceAware());

  String xpathStr = "//aws:OperationRequest";

            XPathFactory xpathFact = XPathFactory.newInstance();

            XPath xpath = xpathFact.newXPath();

        String result = null;
        try {
            result = xpath.evaluate(xpathStr, doc);
        } catch (XPathExpressionException e) {
            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
        }

        System.out.println("XPath result is \"" +  result + "\"");


}
}