in src/main/java/org/apache/sling/scripting/xproc/cocoon/transform/SlingTransformer.java [113:126]
    private TransformerHandler createTransformerHandler() throws Exception {
        SAXTransformerFactory transformerFactory = (SAXTransformerFactory) TransformerFactory.newInstance();
        TemplatesHandler templatesHandler = transformerFactory.newTemplatesHandler();
        XMLReader xmlReader = XMLReaderFactory.createXMLReader();
        xmlReader.setContentHandler(templatesHandler);
        InputSource inputSource = new InputSource(getXsltSource());
        xmlReader.parse(inputSource);
        // Create transformer handler
        final TransformerHandler handler = transformerFactory.newTransformerHandler(templatesHandler.getTemplates());
        return handler;
    }