Java NullPointerException和简化代码

我试着做一个签入表单，我试着设计好它，但我得到了这个错误NullPointer异常。 这是我的密码：

import javax.swing.*;
import javax.swing.border.*;
import java.awt.event.*;
import java.awt.*;
import java.util.*;

public class CheckIn extends JPanel{

    private String[] text = {"  First Name","  Last Name","  Age","  Gender","  Contact No",
            "  Address","  Room Type","  Room No","  Time In","  How many days","  Payment Method"};
    private JPanel designPanel,bottomRightPanel,bottomLeftPanel;
    private String[] genderJCB = {"- Select Gender- ","Male","Female"};
    private String[] roomJCB = {"- Select Room Type -","Classic","Deluxe","Presidential"};
    private JButton submit,cancel;
    private JRadioButton fullRB,depositRB;
    private buttonHandler bh;
    JTextField[] textFields;
    private JComboBox<String> genderBox,roomTypeBox ;
    public CheckIn(){

        //Container settings
        setLayout(null);
        setBackground(new Color(70,70,70));
        //title
        JLabel title = new JLabel("Personal Information",SwingConstants.CENTER);
        title.setBounds(0,0,300,45);
        title.setForeground(Color.ORANGE);
        title.setFont(new Font("Arial",Font.BOLD,13));
        title.setBorder(BorderFactory.createMatteBorder(0,0,1,0,Color.BLACK));  
        add(designPanel());
        add(title);
        //fields
    }
    public JPanel designPanel()
    {
        //Sub container settings
        designPanel = new JPanel( new GridLayout(12,2));
        designPanel.setBounds(0,45,300,505);
        designPanel.setBackground(new Color(80,80,80));
        designPanel.add(bottomLeftPanel());
        designPanel.add(bottomRightPanel());
        return designPanel;
    }
    public JPanel bottomLeftPanel()
    {
        JPanel bottomLeftPanel = new JPanel();
        bottomLeftPanel.setLayout(null);
        bottomLeftPanel.setBorder(BorderFactory.createMatteBorder(1,0,0,0,Color.GRAY));
        bottomLeftPanel.setBackground(new Color(70,70,70));
        bottomButtons();
        return bottomLeftPanel;
    }
    public JPanel bottomRightPanel()
    {
        JPanel bottomRightPanel = new JPanel();
        bottomRightPanel.setLayout(null);
        bottomRightPanel.setBorder(BorderFactory.createMatteBorder(1,0,0,0,Color.GRAY));
        bottomRightPanel.setBackground(new Color(70,70,70));
        bottomButtons();
        return bottomRightPanel;
    }
    public void bottomButtons()
    {
        bh = new buttonHandler();
        cancel = new JButton("Cancel");
        cancel.setBounds(25,4,100,32);
        cancel.addActionListener(bh);
        bottomLeftPanel.add(cancel);
        submit = new JButton("Submit");
        submit.setBounds(25,4,100,32);
        submit.addActionListener(bh);
        bottomRightPanel.add(submit);
    }
    public void components()
    {
        JLabel[] labels = new JLabel[text.length];
        JTextField[] textFields = new JTextField[text.length];
        JPanel[] containerPanel = new JPanel[text.length];



        for(int x = 0; x < text.length; x++){
            //labels
            labels[x] = new JLabel(text[x]);
            labels[x].setForeground(Color.WHITE);
            labels[x].setBorder(new CompoundBorder(BorderFactory.createMatteBorder(1, 0, 0, 0, Color.GRAY),
                    BorderFactory.createMatteBorder(0, 0, 1, 0, Color.BLACK)));
            designPanel.add(labels[x]);
            containerPanel[x]= new JPanel();
            containerPanel[x].setLayout(null);
            containerPanel[x].setBackground(new Color(80,80,80));
            containerPanel[x].setBorder(new CompoundBorder(BorderFactory.createMatteBorder(1, 0, 0, 0, Color.GRAY),
                    BorderFactory.createMatteBorder(0, 0, 1, 0, Color.BLACK)));
            designPanel.add(containerPanel[x]);
            //text fields and etc
            if(x==3){
                genderBox = new JComboBox(genderJCB);
                genderBox.setBounds(0,10,120,25);
                genderBox.setBackground(Color.WHITE);
                containerPanel[x].add(genderBox);
            }
            else if(x==6){
                roomTypeBox = new JComboBox(roomJCB);
                roomTypeBox.setBounds(0,10,145,25);
                roomTypeBox.setBackground(Color.WHITE);
                containerPanel[x].add(roomTypeBox);
            }
            else if(x==8){
                SpinnerDateModel model = new SpinnerDateModel();
                model.setCalendarField(Calendar.MINUTE);
                JSpinner spinner= new JSpinner();
                spinner.setModel(model);
                spinner.setEditor(new JSpinner.DateEditor(spinner, "h:mm a  "));
                spinner.setBounds(0,10,145,25);
                  containerPanel[x].add(spinner);
            }
            else if (x==10){
                ButtonGroup group = new ButtonGroup();
                fullRB = new JRadioButton("Full");
                fullRB.setBounds(0,10,50,25);
                fullRB.setBackground(new Color(80,80,80));
                fullRB.setForeground(Color.white);
                depositRB = new JRadioButton("Deposit");
                depositRB.setBounds(60,10,70,25);
                depositRB.setBackground(new Color(80,80,80));
                depositRB.setForeground(Color.white);
                group.add(fullRB);
                group.add(depositRB);
                containerPanel[x].add(fullRB);
                containerPanel[x].add(depositRB);
            }
            else {
            textFields[x] = new JTextField();
            textFields[x].setBounds(0,10,145,25);
            containerPanel[x].add(textFields[x]);
            }   
        }
    }


    private class buttonHandler implements ActionListener{
        public void actionPerformed(ActionEvent e){

            if(e.getSource() == cancel){

            }   
            else if(e.getSource() == fullRB){

            }
        }
    }

}

import javax.swing.*；
导入javax.swing.border.*；
导入java.awt.event.*；
导入java.awt.*；
导入java.util.*；
公共类签入扩展了JPanel{
私有字符串[]文本={“名字”、“姓氏”、“年龄”、“性别”、“联系人编号”，
“地址”、“房间类型”、“房间号”、“入住时间”、“天数”、“付款方式”}；
专用JPanel设计面板、底部右侧面板、底部左侧面板；
私有字符串[]genderJCB={“-选择性别-”，“男性”，“女性”}；
私有字符串[]roomJCB={”-选择房间类型-“，”经典“，”豪华“，”总统“}；
私有JButton提交、取消；
私人JRadioButton fullRB，存款rb；
私人按钮手柄；
JTextField[]textFields；
私人JComboBox性别箱，roomTypeBox；
公共签入（）{
//容器设置
setLayout（空）；
挫折背景（新颜色（70,70,70））；
//头衔
JLabel title=新的JLabel（“个人信息”，SwingConstants.CENTER）；
标题.立根（0,0300,45）；
标题.设置前景（颜色.橙色）；
title.setFont（新字体（“Arial”，字体粗体，13））；
title.setboorder（BorderFactory.createMatteBorder（0,0,1,0，Color.BLACK））；
添加（设计面板（））；
增加（标题）；
//田地
}
公共JPanel设计小组（）
{
//子容器设置
设计面板=新JPanel（新网格布局（12,2））；
设计小组.立根（0,45300505）；
设计面板.立根背景（新颜色（80,80,80））；
designPanel.add（bottomLeftPanel（））；
designPanel.add（bottomRightPanel（））；
返回设计小组；
}
公共JPanel bottomLeftPanel（）
{
JPanel bottomLeftPanel=新的JPanel（）；
bottomLeftPanel.setLayout（null）；
bottomLeftPanel.setOrder（BorderFactory.createMatteBorder（1,0,0，Color.GRAY））；
底部左侧面板。立根背景（新颜色（70,70,70））；
底部按钮（）；
返回面板；
}
公共JPanel bottomRightPanel（）
{
JPanel bottomRightPanel=新的JPanel（）；
bottomRightPanel.setLayout（空）；
bottomRightPanel.setBorder（BorderFactory.CreateMateBorder（1,0,0，Color.GRAY））；
右下面板.立根背景（新颜色（70,70,70））；
底部按钮（）；
返回右面板；
}
公用按钮（）
{
bh=新按钮手柄（）；
取消=新的JButton（“取消”）；
取消.退步(25,4100,32);；
取消。添加ActionListener（bh）；
底部左侧面板。添加（取消）；
提交=新按钮（“提交”）；
提交.挫折(25,4100,32);；
submit.addActionListener（bh）；
底部右侧面板。添加（提交）；
}
公共void组件（）
{
JLabel[]labels=新的JLabel[text.length]；
JTextField[]textFields=新的JTextField[text.length]；
JPanel[]containerPanel=新的JPanel[text.length]；
对于（int x=0；x

Exception in thread "main" java.lang.NullPointerException
    at CheckIn.bottomButtons(CheckIn.java:73)
    at CheckIn.bottomLeftPanel(CheckIn.java:55)
    at CheckIn.designPanel(CheckIn.java:45)
    at CheckIn.<init>(CheckIn.java:30)
    at HotelMainGUI.leftForms(HotelMainGUI.java:118)
    at HotelMainGUI.leftPanel(HotelMainGUI.java:112)
    at HotelMainGUI.subFrame(HotelMainGUI.java:32)
    at HotelMainGUI.<init>(HotelMainGUI.java:21)
    at HotelMainGUI.main(HotelMainGUI.java:189)

     CheckIn.designPanel() -> bottomLeftPanel() ->  bottomButtons()

    bottomRightPanel.add(submit);

   public JPanel designPanel() {
    //Sub container settings
    designPanel = new JPanel( new GridLayout(12,2));
    designPanel.setBounds(0,45,300,505);
    designPanel.setBackground(new Color(80,80,80));
    designPanel.add(bottomRightPanel());
    designPanel.add(bottomLeftPanel());
    return designPanel;
}

 public JPanel createPanel(){
    JPanel panel = new JPanel();
    panel.setLayout(null);
    panel.setBorder(BorderFactory.createMatteBorder(1,0,0,0,Color.GRAY));
    panel.setBackground(new Color(70,70,70));
    return pannel;
}

   public JPanel designPanel() {
    //Sub container settings
    designPanel = new JPanel( new GridLayout(12,2));
    designPanel.setBounds(0,45,300,505);
    designPanel.setBackground(new Color(80,80,80));
    JPanel leftPanel = createPanel();
    JPanel rightPanel = createPanel();
    createBottomButtons(leftPanel, rightPanel);
    designPanel.add(leftPanel );
    designPanel.add(rightPanel);
    return designPanel;
}