How to extract a fault stacktrace from the SOAP fault using Java

It's..... COMPLICATED!
ps.txt contains the entire fault.... you can adapt to read from a String...

package com.integration.xpath;

import java.io.File;
import java.io.IOException;
import java.util.Iterator;

import javax.xml.XMLConstants;
import javax.xml.namespace.NamespaceContext;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

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

public class XPathRunner {
    public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException, XPathExpressionException {
        doFault();       
    }

    private static void doFault() throws ParserConfigurationException,
    SAXException, IOException, XPathExpressionException {
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        factory.setNamespaceAware(true); // never forget this!
        DocumentBuilder builder = factory.newDocumentBuilder();
        File f = new File("st.txt");
        Document doc = builder.parse(f);
        XPathFactory xpathFactory = XPathFactory.newInstance();
        XPath xpath = xpathFactory.newXPath();
        xpath.setNamespaceContext(new PersonalNamespaceContext());
       
        XPathExpression expr = xpath.compile("//bea_fault:stacktrace/text()");
        Object result = expr.evaluate(doc, XPathConstants.NODESET);
        NodeList nodes = (NodeList) result;
        for (int i = 0; i < nodes.getLength(); i++) {
            Node item = nodes.item(i);
            System.out.println(item.getNodeValue());
        }
    }

  
   
    public static class PersonalNamespaceContext implements NamespaceContext {

        public String getNamespaceURI(String prefix) {
            if (prefix == null) throw new NullPointerException("Null prefix");
            else if ("env".equals(prefix)) return "http://schemas.xmlsoap.org/soap/envelope/";
            else if ("bea_fault".equals(prefix)) return "http://www.bea.com/servers/wls70/webservice/fault/1.0.0";
            else if ("xml".equals(prefix)) return XMLConstants.XML_NS_URI;
            return XMLConstants.NULL_NS_URI;
        }

        // This method isn't necessary for XPath processing.
        public String getPrefix(String uri) {
            throw new UnsupportedOperationException();
        }

        // This method isn't necessary for XPath processing either.
        public Iterator getPrefixes(String uri) {
            throw new UnsupportedOperationException();
        }

    }   
}

thank you to http://www.ibm.com/developerworks/library/x-javaxpathapi.html