JFileChooser nullPointerException.?

Question

Hi all,
I can't seem to debug why I'm getting this error. The error is:
java.lang.NullPointerException
        at raphaelsebayhelper.TakeASeat.actionPerformed(TakeASeat.java:226)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1786)
        at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1839)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:245)
        at java.awt.Component.processMouseEvent(Component.java:5100)
        at java.awt.Component.processEvent(Component.java:4897)
        at java.awt.Container.processEvent(Container.java:1569)
        at java.awt.Component.dispatchEventImpl(Component.java:3615)
        at java.awt.Container.dispatchEventImpl(Container.java:1627)
        at java.awt.Component.dispatchEvent(Component.java:3477)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:3483)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3198)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3128)
        at java.awt.Container.dispatchEventImpl(Container.java:1613)
        at java.awt.Window.dispatchEventImpl(Window.java:1606)
        at java.awt.Component.dispatchEvent(Component.java:3477)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:456)
        at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:145)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)And the error occurs here:
        else if(e.getSource() == fileChooserButton){
--> error line->      int returnval = emailFileChooser.showOpenDialog(this);
            if (returnval == JFileChooser.APPROVE_OPTION){
                File selectedFile = emailFileChooser.getSelectedFile();
                fileAndPathSelected.setText(selectedFile.getAbsolutePath());
        }I've setup my class like this:
public class TakeASeat extends JFrame implements ActionListener{
    private JFrame frame;
    private ImageIcon image = new ImageIcon("takeaseat.JPG");   
    private final JLabel headerFSLabel = new JLabel("", image, SwingConstants.CENTER);
    private JLabel createdBy = new JLabel("created by Sumeet Pathak");
    private Font buttonFont = new Font("Times New Roman", Font.BOLD, 14);
    private String currentDir = "";
    //button Panel
    private JButton kunden;
    private JButton item;
    private JButton orders;
    private JButton emailTransfer;
    // Email Transfer Panel
    private JPanel emailTrPanel;
    private JFileChooser emailFileChooser;
    private JButton fileChooserButton;
    private JTextField fileAndPathSelected;   
    /** Creates new form MyFrame */
    public TakeASeat() {
        frame = new JFrame("Take A Seat");
        Toolkit tk = Toolkit.getDefaultToolkit();
        Dimension d = tk.getScreenSize();
        int screenHeight = d.height;
        int screenWidth = d.width;
        int frameWidth = screenWidth * 2 / 3;
        int frameHeight = screenHeight * 2 / 3;
        frame.setBounds((screenWidth - frameWidth) / 2, (screenHeight - frameHeight) / 2, frameWidth, frameHeight);
        //frame.setResizable(false);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        catch (Exception e){}
        frame.setDefaultLookAndFeelDecorated(true);
        //setup label header and buttons and MenuBar
        JMenuBar myMenuBar = createMenu();
        frame.setJMenuBar(myMenuBar);
        Container contentPane = frame.getContentPane();
        contentPane.add(headerFSLabel, BorderLayout.NORTH);
        contentPane.setBackground(Color.BLUE);
        JPanel bPanel = createButtonPanel();
        contentPane.add(bPanel, BorderLayout.WEST);
        //Display frame
        frame.setVisible(true);
    }That constructor creates my Frame, and adds a button panel on the left side. Now, when a button is clicked on this panel, a corresponding panel is shown at position BorderLayout.CENTER. It is on this panel that the JFileChooser resides. I've tried passing null into the showOpenDialog method and I still get the same result.
Does anyone see something I'm not? If you need more information, let me know what you need and I'll post it.
Thanks.
...DJVege...

Answer 1

Umm..ok! Note, this code is very messy (structure), but I figured I'd clean it up once I had everything running. Economize later. :-)
import javax.swing.*;
import javax.swing.JMenu;
import javax.swing.JMenuItem;
import javax.swing.JMenuBar;
import javax.swing.KeyStroke;
import javax.swing.border.*;
import java.awt.*;
import java.awt.Color;
import java.awt.event.*;
import java.io.*;
/*import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;*/
* @author  Sum
public class TakeASeat extends JFrame implements ActionListener{
    private JFrame frame;
    private ImageIcon image = new ImageIcon("takeaseat.JPG");   
    private final JLabel headerFSLabel = new JLabel("", image, SwingConstants.CENTER);
    private JLabel createdBy = new JLabel("created by Sumeet Pathak");
    private Font buttonFont = new Font("Times New Roman", Font.BOLD, 14);
    private String currentDir = "";
    //button Panel
    private JButton kunden;
    private JButton item;
    private JButton orders;
    private JButton emailTransfer;
    // Email Transfer Panel
    private JPanel emailTrPanel;
    private JFileChooser emailFileChooser;
    private JButton fileChooserButton;
    private JLabel fileAndPathSelected;
    private JTextArea transferOutput;
    /** Creates new form MyFrame */
    public TakeASeat() {
        frame = new JFrame("Take A Seat");
        Toolkit tk = Toolkit.getDefaultToolkit();
        Dimension d = tk.getScreenSize();
        int screenHeight = d.height;
        int screenWidth = d.width;
        int frameWidth = screenWidth * 2 / 3;
        int frameHeight = screenHeight * 2 / 3;
        frame.setBounds((screenWidth - frameWidth) / 2, (screenHeight - frameHeight) / 2, frameWidth, frameHeight);
        //frame.setResizable(false);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        catch (Exception e){}
        frame.setDefaultLookAndFeelDecorated(true);
        //setup label header and buttons and MenuBar
        JMenuBar myMenuBar = createMenu();
        frame.setJMenuBar(myMenuBar);
        Container contentPane = frame.getContentPane();
        contentPane.add(headerFSLabel, BorderLayout.NORTH);
        contentPane.setBackground(Color.BLUE);
        JPanel bPanel = createButtonPanel();
        contentPane.add(bPanel, BorderLayout.WEST);
        //Display frame
        frame.setVisible(true);
    private JMenuBar createMenu(){
        JMenuBar menuBar = new JMenuBar();
        JMenu file = new JMenu("File");
        file.setMnemonic(KeyEvent.VK_F);
        JMenuItem exit = new JMenuItem("Exit");
        exit.addActionListener(this);
        menuBar.add(file);
        file.add(exit);
        return menuBar;
    private void changePanel(JPanel panel){
        Container contentP = frame.getContentPane();
        contentP.add(panel, BorderLayout.CENTER);
        contentP.validate();
    private JPanel createButtonPanel(){
        JPanel buttonPanel = new JPanel();
        String panelHeader = "Functions";
        int headerJustification = TitledBorder.DEFAULT_JUSTIFICATION;
        int headerPosition = TitledBorder.DEFAULT_POSITION;
        Font headerFont = new Font("Times New Roman", Font.BOLD, 13);
        Border bPanelBorder = createBorder(panelHeader, headerJustification, headerPosition, headerFont, Color.WHITE);
        buttonPanel.setBorder(bPanelBorder);
        buttonPanel.setBackground(Color.BLUE.darker().darker());
        buttonPanel.setLayout(new GridLayout(6,1, 20, 15));
        kunden = new JButton("Kunden");
        kunden.setFont(buttonFont);
        kunden.addActionListener(this);
        item = new JButton("Items");
        item.setFont(buttonFont);
        item.addActionListener(this);
        orders = new JButton("Orders");
        orders.setFont(buttonFont);
        orders.addActionListener(this);
        emailTransfer = new JButton("Transfer");
        emailTransfer.setFont(buttonFont);
        emailTransfer.addActionListener(this);
        buttonPanel.add(kunden);
        buttonPanel.add(item);
        buttonPanel.add(orders);
        buttonPanel.add(emailTransfer);
        return buttonPanel;
     * Create the Kunden Panel containing the apporopriate fields/functions
    private JPanel emailTransferPanel(){
        // setup panel
        emailTrPanel = new JPanel();
        SpringLayout layout = new SpringLayout();
        emailTrPanel.setLayout(layout);
        emailTrPanel.setBackground(Color.LIGHT_GRAY);
        // Setup components in panel
        String emailTrHeader = "Transfter Data From Email File";
        int eTrheaderJust = TitledBorder.DEFAULT_JUSTIFICATION;
        int eTrheaderPos = TitledBorder.DEFAULT_POSITION;
        Font eTrheaderFont = new Font("Times New Roman", Font.BOLD, 13);
        Border emailTrBorder = createBorder(emailTrHeader, eTrheaderJust, eTrheaderPos, eTrheaderFont, Color.WHITE);
        emailTrPanel.setBorder(emailTrBorder);
        Font bFont = new Font("Times New Roman", Font.PLAIN, 14);       
        JLabel infoLabel = new JLabel("Select file to transfer details from");
        infoLabel.setFont(bFont);
        fileChooserButton = new JButton("Browse");
        fileChooserButton.setFont(bFont);
        Dimension bSize = new Dimension(150, 30);
        fileChooserButton.setPreferredSize(bSize);
        fileChooserButton.addActionListener(this);
        fileAndPathSelected = new JLabel();
        fileAndPathSelected.setBorder(BorderFactory.createCompoundBorder(BorderFactory.createEtchedBorder(), BorderFactory.createLoweredBevelBorder()));
        fileAndPathSelected.setBackground(Color.WHITE);
        fileAndPathSelected.setOpaque(true);
        fileAndPathSelected.setFont(bFont);
        Dimension textFieldSize = new Dimension(300, 30);
        fileAndPathSelected.setPreferredSize(textFieldSize);
        fileAndPathSelected.setFont(bFont);
        Dimension scrollPaneSize = new Dimension(400,200);       
        transferOutput = new JTextArea();
        transferOutput.setPreferredSize(scrollPaneSize);
        transferOutput.setMargin(new Insets(5,5,5,5));
        transferOutput.setEditable(false);
        transferOutput.setCursor(null);
        JScrollPane scrollPane = new JScrollPane(transferOutput, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
        scrollPane.setPreferredSize(scrollPaneSize);
        JLabel outputLabel = new JLabel("Results");
        outputLabel.setFont(bFont);
        emailTrPanel.add(infoLabel);
        emailTrPanel.add(fileChooserButton);
        emailTrPanel.add(fileAndPathSelected);
        emailTrPanel.add(outputLabel);
        emailTrPanel.add(scrollPane);
        layout.putConstraint(SpringLayout.WEST, infoLabel, 10, SpringLayout.WEST, emailTrPanel);
        layout.putConstraint(SpringLayout.NORTH, infoLabel, 0, SpringLayout.NORTH, emailTrPanel);
        layout.putConstraint(SpringLayout.WEST, fileAndPathSelected, 10, SpringLayout.WEST, emailTrPanel);
        layout.putConstraint(SpringLayout.NORTH, fileAndPathSelected, 20, SpringLayout.NORTH, emailTrPanel);
        layout.putConstraint(SpringLayout.WEST, fileChooserButton, 5, SpringLayout.EAST, fileAndPathSelected);
        layout.putConstraint(SpringLayout.NORTH, fileChooserButton, 20, SpringLayout.NORTH, emailTrPanel);
        layout.putConstraint(SpringLayout.WEST, scrollPane, 30, SpringLayout.WEST, emailTrPanel);
        layout.putConstraint(SpringLayout.SOUTH, scrollPane, -10, SpringLayout.SOUTH, emailTrPanel);
        layout.putConstraint(SpringLayout.WEST, outputLabel, 30, SpringLayout.WEST, emailTrPanel);
        layout.putConstraint(SpringLayout.SOUTH, outputLabel, -5, SpringLayout.NORTH, scrollPane);
        return emailTrPanel;
    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == kunden){
            emailTransfer.setEnabled(true);
            kunden.setEnabled(false);
            item.setEnabled(true);
            orders.setEnabled(true);           
            System.out.println("kunden");
        else if (e.getSource() == item){
            emailTransfer.setEnabled(true);
            kunden.setEnabled(true);
            item.setEnabled(false);
            orders.setEnabled(true);           
            System.out.println("item");
        else if (e.getSource() == orders){
            emailTransfer.setEnabled(true);
            kunden.setEnabled(true);
            item.setEnabled(true);
            orders.setEnabled(false);
            System.out.println("orders");
        else if (e.getSource() == emailTransfer){
            emailTransfer.setEnabled(false);
            kunden.setEnabled(true);
            item.setEnabled(true);
            orders.setEnabled(true);
            JPanel emailT = emailTransferPanel();
            changePanel(emailT);
            /*String msaccesspath = "F:\\Program Files\\Microsoft Office\\OFFICE11\\MSACCESS.EXE"; // path to MSACCESS.EXE
            String databasepath = "G:\\Raphael-Adresse-Kunden.mdb";
            EmailReader er = new EmailReader();         
            // Converting DBX file
            try {
                System.out.println("Please wait. Converting DBX file...");
                er.convertDBXFile();
                System.out.println("File converted successfully!");
            }catch(Exception ex){
                System.out.println("Error in converting" + "\n" + e);
                System.exit(0);
            // Extracting Data
            try {
                er.getData();
            } catch(Exception ex) {
                System.out.println("Error extracting data" + "\n" + e);
                System.exit(0);
            // Transfer to Database
            er.transferToDB();
            System.out.println("All Details transferred Successfully");*/         
        else if(e.getSource() == fileChooserButton){
            int returnval = emailFileChooser.showOpenDialog(this);
            if (returnval == JFileChooser.APPROVE_OPTION){
                File selectedFile = emailFileChooser.getSelectedFile();
                fileAndPathSelected.setText(selectedFile.getAbsolutePath());
    private Border createBorder(String borderTitle, int justification, int position, Font font, Color stringColour){
        Border etchedBorder = BorderFactory.createEtchedBorder();
        Border titleBorder = BorderFactory.createTitledBorder(etchedBorder, borderTitle, justification, position, font, stringColour);
        Border etchedAroundTitle = BorderFactory.createCompoundBorder(etchedBorder, titleBorder);
        Border emptyBorderInner = BorderFactory.createEmptyBorder(15, 15, 0, 15);
        Border emptyBorderOuter = BorderFactory.createEmptyBorder(5, 5, 0, 5);
        Border titleOutsideEmpty = BorderFactory.createCompoundBorder(titleBorder, emptyBorderInner);
        Border emptyOutsideTitle = BorderFactory.createCompoundBorder(emptyBorderOuter, titleOutsideEmpty);
        return emptyOutsideTitle;
     * @param args the command line arguments
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new TakeASeat();
    // Variables declaration - do not modify
    // End of variables declaration
}That should run.