Java Utililty Methods XML Transform Usage

XMLSignatureFactory fac = initXMLSigFactory();
NodeList nl = element.getElementsByTagNameNS(XMLSignature.XMLNS, "Signature");
if (nl.getLength() == 0) {
    throw new RuntimeException("Cannot find Signature element");
DOMValidateContext valContext = new DOMValidateContext(validatingKey, nl.item(0));
try {
    valContext.setProperty("javax.xml.crypto.dsig.cacheReference", Boolean.TRUE);
...

DOMSource domSource = new DOMSource(element);
XMLEventReader parser = inputFactory.createXMLEventReader(domSource);
StartElement startElement;
Characters characters;
while (parser.hasNext()) {
    XMLEvent event = parser.nextEvent();
    switch (event.getEventType()) {
    case XMLStreamConstants.START_ELEMENT:
...

try {
    XMLFilter filter = null;
    for (Templates tplt : templates) {
        XMLFilter nextFilter = saxTf.newXMLFilter(tplt);
        if (filter != null)
            nextFilter.setParent(filter);
        filter = nextFilter;
    Transformer htmlTransformer = saxTf.newTransformer();
    SAXSource transformSource = new SAXSource(filter, new InputSource(inputStream));
    htmlTransformer.setOutputProperty(OutputKeys.METHOD, "xml");
    htmlTransformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
    htmlTransformer.setOutputProperty(OutputKeys.DOCTYPE_PUBLIC, "-//W3C//DTD XHTML 1.0 Strict//EN");
    htmlTransformer.setOutputProperty(OutputKeys.DOCTYPE_SYSTEM,
            "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd");
    htmlTransformer.transform(transformSource, new StreamResult(writer));
} catch (TransformerConfigurationException e) {
    throw new RuntimeException(e);
} catch (TransformerException e) {
    throw new RuntimeException(e);

try {
    TransformerFactory factory = TransformerFactory.newInstance();
    Templates template = factory.newTemplates(new StreamSource(xslStream));
    Transformer xformer = template.newTransformer();
    Source source = new StreamSource(new FileInputStream(inFile));
    Result result = new StreamResult(new FileOutputStream(outFile));
    xformer.transform(source, result);
} catch (TransformerException e) {
...