Validating via JUnit

  public void testValidOutput() throws SAXException, IOEXception {

  File f = new File("filename.xml");
  InputSource in = new InputSource(new FileInputStream(f));
  
  XMLReader parser = XMLReaderFactory.createXMLReader(); 
  parser.setFeature("http://xml.org/sax/features/validation", true);
  parser.setErrorHandler(new ErrorHandler() {

  public void warning(SAXParseException exception) {
    // skip
  }

  public void error(SAXParseException exception) 
   throws SAXException {
    throw exception;  
  }

  public void fatalError(SAXParseException exception) 
   throws SAXException {
    throw exception;   
  }
    
  });
  parser.parse(in);

}