Creating a new Document:

DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = null;
Document doc = null;
try {
    docBuilder = docBuilderFactory.newDocumentBuilder();
    doc = docBuilder.newDocument();
}
catch (ParserConfigurationException e) {
    e.printStackTrace();
};

Creating a new Jena model:

ModelFactory.createDefaultModel();