我是新手，下面只是想显示如图界面，但显示不出来，各位麻烦看一下
我是新手，下面只是想显示如图界面，但显示不出来，各位麻烦看一下:

public class AddStudentFrame extends javax.swing.JFrame {

    /** Creates new form AddStudentFrame */
    public AddStudentFrame() {
        initComponents();
    }
   // @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {

        jLabelStudentID = new javax.swing.JLabel();
        jLabelGender = new javax.swing.JLabel();
        jLabelGrade = new javax.swing.JLabel();
        jLabelPhoneNum = new javax.swing.JLabel();
        jLabelStudentName = new javax.swing.JLabel();
        jTextFieldName = new javax.swing.JTextField();
        jTextFieldStudentID = new javax.swing.JTextField();
        jTextFieldGrade = new javax.swing.JTextField();
        jTextFieldPhoneNum = new javax.swing.JTextField();
        jRadioButton1 = new javax.swing.JRadioButton();
        jRadioButton2 = new javax.swing.JRadioButton();
        jButton1 = new javax.swing.JButton();
        jButton2 = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jLabelStudentID.setText("学号：");

        jLabelGender.setText("性别：");

        jLabelGrade.setText("班级：");

        jLabelPhoneNum.setText("联系电话：");

        jLabelStudentName.setText("姓名：");

        jRadioButton1.setSelected(true);
        jRadioButton1.setText("男");

        jRadioButton2.setText("女");

        jButton1.setText("确定");

        jButton2.setText("取消");

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(48, 48, 48)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)