输出显示在新选项卡式窗格中

Question

我有一个项目（使用netbeans）来创建GUI。我的计划是在新的标签窗格中显示我的输出列表。
这是我的计划：
我想使用我的生成器生成测试集。在设置输入之后，用户需要单击“生成”按钮。用户可以在新的选项卡式窗格中显示测试集列表。

我的结果：我没有错误，但我无法将结果输出到输出选项卡式窗格

package rtg;   
public class SamplesJFrame extends javax.swing.JFrame {
    public SamplesJFrame() {
            initComponents();
        }
private void initComponents() {

        jTabbedPane1 = new javax.swing.JTabbedPane();
        jPanel1 = new javax.swing.JPanel();
        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        jScrollPane1 = new javax.swing.JScrollPane();
        jTextArea1 = new javax.swing.JTextArea();
        jButton1 = new javax.swing.JButton();
        jScrollPane4 = new javax.swing.JScrollPane();
        jTextArea4 = new javax.swing.JTextArea();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

jButton2.setText("Generate");
        jButton2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton2ActionPerformed(evt);
            }
        });
jTabbedPane1.addTab("Actual Input", jPanel1);
jTabbedPane1.addTab("Output", jPanel3);

}
private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
        // TODO add your handling code here:
        input = input.substring(0,input.length()-1);

                        Datamanager input_final = new Datamanager();
                        input_final.setActualInput(input);
                        String value_set = input_final.getFinalInput();

                        Generator gen = new Generator();
                        gen.insertSystemSetting(value_set);
                        gen.insertStrength(Integer.parseInt(jTextField2.getText()));

                        gen.solve();
                        ArrayList<String> test_set = gen.getResult();

                        input_final.setActualOutput(test_set);
                        ArrayList<String> result_set = input_final.getActualResult();


                                    int j=1;
                                    for(Iterator it = result_set.iterator(); it.hasNext();)
                                    {
                                        String data = (String)it.next();
                                        jTextArea4.append(j+" => "+data+"\n"); //this is what i want to display in textarea4 in jpanel3.but looks like sumthing missing
                                        j++;
                                }
    }

 public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {
                new SamplesJFrame().setVisible(true);
            }
        });

//variables declaration
    }


}