在 JFrame类里面添加方法报错

public class DynamicArray extends JFrame {
private JPanel contentPane;
private JTextField textField;
/**
 * Launch the application.
 */
public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                DynamicArray frame = new DynamicArray();
                frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}
/**
 * Create the frame.
 */
private ArrayList<String> arraylist = new ArrayList<String>();
public DynamicArray() {
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setBounds(100, 100, 450, 300);
    contentPane = new JPanel();
    contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
    setContentPane(contentPane);
    contentPane.setLayout(null);
    JList list = new JList();
    list.setBounds(25, 82, 198, 155);
    contentPane.add(list);
    JLabel label = new JLabel("\u5B66\u751F\u59D3\u540D\uFF1A");
    label.setBounds(25, 20, 65, 30);
    contentPane.add(label);
    textField = new JTextField();
    textField.setBounds(104, 23, 121, 25);
    contentPane.add(textField);
    textField.setColumns(10);
    JButton btnNewButton = new JButton("添加学生");
    btnNewButton.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            //执行动作
            textField.requestFocusInWindow();
            textField.selectAll();// 选择文本框文本准备下次输入
            String text = textField.getText();// 获取用户输入姓名
            if (text.isEmpty())// 过滤为输入姓名的情况
                return;
            arraylist.add(text);// 把姓名添加到数组集合中
// replaceModel();// 把数组集合中内容显示到界面列表控件中
}
});
btnNewButton.setBounds(300, 27, 93, 23);
contentPane.add(btnNewButton);
    JButton btnNewButton_1 = new JButton("删除学生");
    btnNewButton_1.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            //执行动作
        }
    });
    btnNewButton_1.setBounds(300, 94, 93, 23);
    contentPane.add(btnNewButton_1);

private void replaceModel()
这个地方报了三个错误