. lang。不能对DeepNodeListImpl进行cast

here is my code :

这是我的代码:

 public void Login() {  
    try{
        DocumentBuilderFactory builderfactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder db = builderfactory.newDocumentBuilder();

        File path = new File("src/dataPengguna/dataPengguna.xml");

        Document doc = db.parse(path);

        Element pengguna = (Element) doc.getElementsByTagName("pengguna");

        NodeList list = pengguna.getElementsByTagName("user");

        for (int i = 0; i < list.getLength(); i++) {
            Element user =  (Element) list.item(i);
            Node username =   user.getElementsByTagName("username").item(i);
            Node password =   user.getElementsByTagName("password").item(i);

            if(loginuser.getText().equals(username.getTextContent()) 
               && loginpass.getText().equals(password.getTextContent())){ 
                JOptionPane.showMessageDialog(rootPane, "welcome");
            }
        }
    }catch(Exception e){
      e.printStackTrace();

    }
    }
 public void Log