Develop Reference

Retrieving filename from Jfilechooser into JList

I'm having some problems with my class that I need some help with. The class is supposed to take retrieve a csv.file from the file chooser, and then put the name of the file into a Jlist, but I can't get the JList to print the arraylist that I put the chosen files into. This is the code I've got, so I'd be grateful if you could take a look at it and tell me what I need to change with it in order to get the JList to print the arraylist.
import dao.UserDAO;
import db.DemoDB;
import model.Activity;
import model.DataPoint;
import model.Statistics;
public class LoginGUI1 {
DemoDB DemoDBSingleton = null;
private JTabbedPane tabbedPane = new JTabbedPane();
UserDAO userDao = new UserDAO();
JFrame mainFrame = new JFrame("Välkommen till din app");
JFrame f = new JFrame("User Login");
JLabel l = new JLabel("Användarnamn:");
JLabel l1 = new JLabel("Lösenord:");
JTextField textfieldUsername = new JTextField(10);
JPasswordField textfieldPassword = new JPasswordField(10);
JButton loginButton = new JButton("Logga In");
JFileChooser fc = new JFileChooser();
JMenuBar mb = new JMenuBar();
JList listAct = new JList();
List<Activity> activityList = new ArrayList<Activity>();
List activityList1 = new Vector();
JFrame jf;
JMenu menu;
JMenuItem importMenu, exitMenu;
Activity activity = new Activity();
public LoginGUI1() throws IOException {
DemoDBSingleton = DemoDB.getInstance();
ProgramMainFrame();
}
private void ProgramMainFrame() throws IOException {
mainFrame.setSize(800, 600);
mainFrame.setVisible(true);
mainFrame.setJMenuBar(mb);
mainFrame.getContentPane().setLayout(new BorderLayout());;
tabbedPane.add("Dina Aktiviteter", createViewActPanel());
mainFrame.getContentPane().add(tabbedPane, BorderLayout.CENTER);
tabbedPane.add("Diagram för vald aktivitet", createViewDiagramPanel());
tabbedPane.add("Statistik för vald aktivitet", createViewStatisticsPanel());
tabbedPane.add("Kartbild över vald aktivitet", createViewMapPanel());
JMenuBar mb = new JMenuBar();
menu = new JMenu("Meny");
importMenu = new JMenuItem("Importera aktivitet");
importMenu.addActionListener(importActionListener);
exitMenu = new JMenuItem("Avsluta program");
exitMenu.addActionListener(exitActionListener);
menu.add(importMenu);
menu.add(exitMenu);
mb.add(menu);
mainFrame.setJMenuBar(mb);
/* JPanel listholder = new JPanel();
listholder.setBorder(BorderFactory.createTitledBorder("ListPanel"));
mainFrame.add(listholder);
listholder.setVisible(true);
listholder.setSize(500,400);*/
}
private JPanel createViewActPanel() {
JPanel analogM = new JPanel();
analogM.setBackground(new Color(224, 255, 255));
return analogM;
}
ActionListener importActionListener = new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
int returnValue = fc.showOpenDialog(mainFrame);
if(returnValue == JFileChooser.APPROVE_OPTION)
{
File file = fc.getSelectedFile();
if(file != null)
{
String fileName = file.getAbsolutePath();
Activity activity = null;
try {
activity = new Activity();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
activity.csvFileReader(fileName);
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
activityList.add(activity);
listAct.setListData(activityList.toArray());
}
}
}
};
public static void main(String[] args) throws IOException {
new LoginGUI();
}
}

There's a lot of context missing, so the best I can do is provide a simple running example which works.
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
public class Test {
public static void main(String args[]) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private JList<File> fileList;
private DefaultListModel<File> fileListModel;
public TestPane() {
fileListModel = new DefaultListModel<>();
fileList = new JList(fileListModel);
JButton addButton = new JButton("Add");
addButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent arg0) {
JFileChooser fileChooser = new JFileChooser();
if (fileChooser.showOpenDialog(TestPane.this) == JFileChooser.APPROVE_OPTION) {
File file = fileChooser.getSelectedFile();
fileListModel.addElement(file);
}
}
});
setLayout(new BorderLayout());
add(new JScrollPane(fileList));
add(addButton, BorderLayout.SOUTH);
}
}
}
I'd highly recommend having a look at How to use lists to get a better understanding of how the API works

Use JTable in another class

The code below takes data from a text file delimited by "|" and displays it in a JTable. When I run it on the JFrame itself it does work. However I cannot figure out how to move it to another class for itself and make it become a method such as public void viewUser(){}, then call it from the frame on click of a button.
public void viewUser(){
File file = new File("user.dat");
try {
FileReader fr = new FileReader(file);
BufferedReader br = new BufferedReader(fr);
DefaultTableModel model = (DefaultTableModel)jTable1.getModel();
Object[] lines = br.lines().toArray();
for (Object line : lines) {
String[] row = line.toString().split("\\|");
model.addRow(row);
}
} catch (IOException ex) {
Logger.getLogger(UserManagement.class.getName()).log(Level.SEVERE, null, ex);
}

You are getting this wrong conceptually: a model by itself is meaningless. It needs to be connected to a table in order to show its content.
The code you are showing is creating and filling a new table model. Then that model and all the information is thrown away. Reading data into an object is pointless, when that object isn't made available for further usage!
You might simply change the return type from void to DefaultTableModel and return the model object in the end. And then you can use that pre-filled model for any JTable!

Run this mcve and see if it mocks what you want to do:
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
public class TablePane extends JPanel {
private final JTable table;
public TablePane() {
super(new GridLayout(1,0));
String[] columnNames = {"Name", "Age" };
Object[][] data = {
{"Kathy", new Integer(35)},
{"John", new Integer(63)},
{"Sue", new Integer(28)},
{"Joe", new Integer(70)}
};
DefaultTableModel model = new DefaultTableModel(data, columnNames);
table = new JTable(model);
table.setPreferredScrollableViewportSize(new Dimension(300, 100));
table.setFillsViewportHeight(true);
JScrollPane scrollPane = new JScrollPane(table);
add(scrollPane);
}
void refresh() {
new Updater(table).getNewData();
}
private static void createAndShowGUI() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
TablePane tablePane = new TablePane();
frame.add(tablePane);
JButton button = new JButton("Change data");
button.addActionListener(e -> tablePane.refresh());
frame.add(button, BorderLayout.NORTH);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
createAndShowGUI();
}
});
}
}
class Updater {
private DefaultTableModel model;
Object[][] testData = {
{"Bon", new Integer(15)},
{"Anna", new Integer(31)},
{"Dan", new Integer(82)},
{"Jane", new Integer(20)},
};
public Updater(JTable table) {
model = (DefaultTableModel)table.getModel();
}
void getNewData(){
//if you want to clear data : model.getDataVector().clear();
for (Object[] row : testData) {
model.addRow(row);
}
}
}
As commented by Andrew Thomson mcve with hard coded data is essential.

Importing text into a JTable is not displaying

I have created a program where I can input data in JTextField and on hitting save button I use a JFileChooser to save the data in a .txt file where each JTextField is in a new line. I also created a button that pops up a JFileChooser to browse for that file and populate its corresponding cells.
I am new to GUIs, the code I wrote is not working. I tried different variations and cannot seem to get it. Can someone point me in the right direction please.
The input is
john
Doe
st. Jude
100
Here is the code
import javax.swing.*;
import javax.swing.filechooser.FileNameExtensionFilter;
import javax.swing.table.DefaultTableModel;
import java.util.Scanner
import java.util.Vector;
import java.awt.event.*;
import java.awt.*;
import java.text.DecimalFormat;
import java.io.*;
//import javax.swing.filechooser;
import javax.swing.filechooser.FileFilter;
public class Charity
{
#SuppressWarnings("deprecation")
public static void main(String[] args)
{
JFrame frame = new JFrame("Learning Team Charity Program");
Container cp = frame.getContentPane();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Charities
final String[] charityArray = {"St.Jude", "CHOC", "Cancer Research", "AIDs Foundation", "Crohns Foundation"};
final JComboBox selector = new JComboBox(charityArray);
JPanel first = new JPanel();
first.setLayout(new FlowLayout());
first.add(selector);
// User input JLabels and JTextFields
JLabel nameLabel = new JLabel("First Name: ");
final JTextField name = new JTextField();
JLabel lastLabel = new JLabel("Last Name: ");
final JTextField lastname = new JTextField();
JLabel donationAmount = new JLabel("Donation Amount: ");
final JTextField donation = new JTextField();
JPanel second = new JPanel();
second.setLayout(new GridLayout(4,2));
second.add(nameLabel); second.add(name);
second.add(lastLabel); second.add(lastname);
second.add(donationAmount); second.add(donation);
// Donate & Exit Buttons
JButton donateButton = new JButton("Donate");
JButton saveButton = new JButton("Save");
JButton exitButton = new JButton("Exit");
JButton openButton= new JButton("Open File");
JPanel third = new JPanel();
third.setLayout(new FlowLayout());
third.add(donateButton);
third.add(saveButton);
third.add(openButton);
third.add(exitButton);
// JTable display
final DefaultTableModel model = new DefaultTableModel();
JTable table = new JTable(model);
model.addColumn("First Name");
model.addColumn("Last Name");
model.addColumn("Charity");
model.addColumn("Donation");
table.setShowHorizontalLines(true);
table.setRowSelectionAllowed(true);
table.setColumnSelectionAllowed(true);
JScrollPane scrollPane = JTable.createScrollPaneForTable(table);
JPanel fourth = new JPanel();
fourth.setLayout(new BorderLayout());
fourth.add(scrollPane, BorderLayout.CENTER);
// Button Events
exitButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
System.exit(1);
}
});
openButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e){
JFileChooser openChooser = new JFileChooser();
int openStatus = openChooser.showOpenDialog(null);
if(openStatus == JFileChooser.APPROVE_OPTION){
try{
File myFile = openChooser.getSelectedFile();
BufferedReader br = new BufferedReader(new FileReader(myFile));
String line;
while((line = br.readLine())!= null){
model.addRow(line.split(","));
}//end while
br.close();
}//end try
catch(Exception e2){
JOptionPane.showMessageDialog(null, "Buffer Reader Error");
}//end catch
}
}
private void setValueAt(String line, int row, int col) {
// TODO Auto-generated method stub
}
});
saveButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e){
JFileChooser fileChooser = new JFileChooser();
int status = fileChooser.showSaveDialog(null);
if (status == JFileChooser.APPROVE_OPTION)
{
fileChooser.addChoosableFileFilter(new FileNameExtensionFilter("Text", ".txt", "txt"));
//fileChooser.setFileFilter(new FileFilter("txt"));
PrintWriter output;
try {
File file = fileChooser.getSelectedFile();
output = new PrintWriter(file +".txt");
for(int row = 0; row<table.getRowCount(); row++){
for(int col = 0; col<table.getColumnCount();col++){
output.println(table.getValueAt(row, col).toString());
}
output.println();
}
output.close();
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
});
donateButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
DecimalFormat df = new DecimalFormat("##,###.00");
try
{
Object[] rows = new Object[]{name.getText(), lastname.getText(), selector.getSelectedItem(),
donation.getText()};
model.addRow(rows);
name.setText("");
lastname.setText("");
donation.setText("");
}
catch (Exception ex)
{
JOptionPane.showMessageDialog(null, "Enter a Dollar Amount", "Alert", JOptionPane.ERROR_MESSAGE);
return;
}
}
});
// Frame Settings
frame.setSize(470,300);
//frame.setLocation(300,200);
cp.setLayout(new BoxLayout(cp, BoxLayout.Y_AXIS));
cp.add(first);
cp.add(second);
cp.add(third);
cp.add(fourth);
frame.setVisible(true);
}
}

I understand I have to pass a value in the parenthesis after the addRow.
People don't know what that means because the code you posted here doesn't have an addRow(...) method.
I see you posted a second question 2 hours later: https://stackoverflow.com/questions/30951407/how-to-properly-read-a-txt-file-into-a-a-row-of-a-jtable.
Keep all the comments in one place so people understand what is going on.
Also, posting a few random lines of code doesn't help us because we don't know the context of how the code is used. For example, I have no idea what how you created the "model" variable. I don't know if you ever added the model to the table.
Post a proper SSCCE when posting a question so we have the necessary information. The file chooser is irrelevant to the problem because we don't have access to your real file. So instead you need to post hard coded data. An easy way to do this is to use a StringReader.
Here is a working example that shows how to read/parse/load a file into a JTable:
import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.table.*;
import java.io.*;
public class SSCCE extends JPanel
{
public SSCCE()
{
try
{
DefaultTableModel model = new DefaultTableModel(0, 4);
String data = "1 2 3 4\na b c d\none two three four";
BufferedReader br = new BufferedReader( new StringReader( data ) );
String line;
while ((line = br.readLine()) != null)
{
String[] split = line.split(" ");
model.addRow( split );
}
JTable table = new JTable(model);
add( new JScrollPane(table) );
}
catch (IOException e) { System.out.println(e); }
}
private static void createAndShowGUI()
{
JFrame frame = new JFrame("SSCCE");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new SSCCE());
frame.setLocationByPlatform( true );
frame.pack();
frame.setVisible( true );
}
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
createAndShowGUI();
}
});
}
}
All you need to do is change the code to use a FileReader instead of the StringReader.

I figured it out. Thanks for all those that tried to help.
openButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e){
JFileChooser openChooser = new JFileChooser();
int openStatus = openChooser.showOpenDialog(null);
if(openStatus == JFileChooser.APPROVE_OPTION){
try{
File myFile = openChooser.getSelectedFile();
//BufferedReader br = new BufferedReader(new FileReader(myFile));
Scanner br = new Scanner(new FileReader(myFile));
String line;
while((line = br.nextLine())!= null){
Object[] myRow = new Object[]{line,br.nextLine(), br.nextLine(), br.nextLine()};
model.addRow(myRow);
// line = br.readLine();
if(br.nextLine()== " "){
line=br.nextLine();
}
}//end while
br.close();
}//end try
catch(Exception e2){
return;
}//end catch
}
}
});

Fetch from external file and display in a JTable

Can someone tell me how to modify below program? Program's data is passed by object[][] - instead of that will just give file name which is having data should be print in a table.
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
public class SimpleTableDemo extends JPanel {
private boolean DEBUG = false;
public SimpleTableDemo() {
super(new GridLayout(1,0));
String[] columnNames = {"First Name",
"Last Name",
"Sport",
"# of Years",
"Vegetarian"};
Object[][] data = {
{"Kathy", "Smith",
"Snowboarding", new Integer(5), new Boolean(false)},
{"John", "Doe",
"Rowing", new Integer(3), new Boolean(true)},
{"Sue", "Black",
"Knitting", new Integer(2), new Boolean(false)},
{"Jane", "White",
"Speed reading", new Integer(20), new Boolean(true)},
{"Joe", "Brown",
"Pool", new Integer(10), new Boolean(false)}
};
final JTable table = new JTable(data, columnNames);
table.setPreferredScrollableViewportSize(new Dimension(500, 70));
table.setFillsViewportHeight(true);
if (DEBUG) {
table.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
printDebugData(table);
}
});
}
//Create the scroll pane and add the table to it.
JScrollPane scrollPane = new JScrollPane(table);
//Add the scroll pane to this panel.
add(scrollPane);
}
private void printDebugData(JTable table) {
int numRows = table.getRowCount();
int numCols = table.getColumnCount();
javax.swing.table.TableModel model = table.getModel();
System.out.println("Value of data: ");
for (int i=0; i < numRows; i++) {
System.out.print(" row " + i + ":");
for (int j=0; j < numCols; j++) {
System.out.print(" " + model.getValueAt(i, j));
}
System.out.println();
}
System.out.println("--------------------------");
}
/**
* Create the GUI and show it. For thread safety,
* this method should be invoked from the
* event-dispatching thread.
*/
private static void createAndShowGUI() {
//Create and set up the window.
JFrame frame = new JFrame("SimpleTableDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Create and set up the content pane.
SimpleTableDemo newContentPane = new SimpleTableDemo();
newContentPane.setOpaque(true); //content panes must be opaque
frame.setContentPane(newContentPane);
//Display the window.
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}

If I understood question correct, you can replace Object[][] data with something like this:
String line;
ArrayList<String[]> toData = new ArrayList<String[]>();
File file = new File("\\file path");
try{
BufferedReader reader = new BufferedReader(new FileReader(file));
while ((line = reader.readLine()) != null) {
String[] lineElements = line.split(",");
toData.add(lineElements);
}
}catch (Exception ex){
ex.printStackTrace();
System.out.println("File not found");
}
String[][] data = new String[toData.size()][];
int index = 0;
for(String[] a: toData){
data[index]=a;
index++;
}
In this exemple, it will work if data in file is formatted as:
name, surname, sportage, is Vegetarian. However you can change that easily, but remember to also change symbol in brackets in line.split().
EDIT:
I don't fully understand what you want to achieve, however I would do it like this:
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.*;
import java.util.ArrayList;
public class Project {
private JScrollPane scrollPane;
private JFrame frame;
private JTable table;
public static void main (String[] args){
Project project = new Project();
project.createGUI();
}
public void createGUI(){
frame = new JFrame();
scrollPane = new JScrollPane();
JPanel panel = new JPanel();
JButton open = new JButton("Open");
open.addActionListener(new OpenListener());
JButton submit = new JButton("Submit");
submit.addActionListener(new SubmitListener());
JButton cancel = new JButton("Cancel");
cancel.addActionListener(new CancelListener());
panel.add(open);
panel.add(submit);
panel.add(cancel);
frame.getContentPane().add(BorderLayout.CENTER,scrollPane);
frame.getContentPane().add(BorderLayout.SOUTH,panel);
frame.setSize(500,500);
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.setVisible(true);
}
public void createAndDisplayList(String[][] data){
String[] columnNames = {"First Name","Last Name","Sport","# of Years","Vegetarian"};
table = new JTable(data, columnNames);
frame.setVisible(false);
frame.remove(scrollPane);
scrollPane = new JScrollPane(table);
frame.getContentPane().add(BorderLayout.CENTER,scrollPane);
frame.revalidate();
frame.setVisible(true);
}
private class OpenListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
JFileChooser fileChooser = new JFileChooser();
String line;
ArrayList<String[]> toData = new ArrayList<String[]>();
fileChooser.showOpenDialog(frame);
try{
BufferedReader reader = new BufferedReader(new FileReader(fileChooser.getSelectedFile()));
while ((line = reader.readLine()) != null) {
String[] lineElements = line.split(",");
toData.add(lineElements);
}
reader.close();
}catch (Exception ex){
ex.printStackTrace();
JOptionPane.showMessageDialog(frame, "File not found", "Error", JOptionPane.ERROR_MESSAGE);
}
String[][] data = new String[toData.size()][];
int index = 0;
for(String[] a: toData){
data[index]=a;
index++;
}
createAndDisplayList(data);
}
}
private class CancelListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
frame.remove(scrollPane);
scrollPane = new JScrollPane();
frame.getContentPane().add(BorderLayout.CENTER,scrollPane);
frame.revalidate();
frame.setVisible(true);
}
}
private class SubmitListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
JFileChooser fileChooser = new JFileChooser();
fileChooser.showSaveDialog(frame);
try{
BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(fileChooser.getSelectedFile()));
for(int i = 0; i<table.getRowCount(); i++){
for(int j = 0; j<table.getColumnCount(); j++){
System.out.println(i + "," + table.getRowCount());
bufferedWriter.write(table.getValueAt(i, j).toString() + ",");
}
bufferedWriter.newLine();
}
bufferedWriter.close();
}catch (IOException ex){
ex.printStackTrace();
JOptionPane.showMessageDialog(frame,"File not found","Error",JOptionPane.ERROR_MESSAGE);
}
}
}
}
However be aware it is a primitive and amateur written code, but it works to some extent. You can open, change content and save file(submit), but you cannot add rows in table, you need to do it in .txt file (but you cannot leave any empty space at the end of file).
Anyway, I hope you will find something usufull here.

Java adding Menu to Frame

I am trying to write a clipboard program that can copy/paste and save to a txt file.
While the program works, I am trying to change the buttons into a Menu with MenuItems,
however, I cannot figure out how to use the Menu item properly, as I cannot add it to a panel.
Please notice I am using AWT and not Swing, so no JPanel/JFrame, etc.
Any tip/help is appreciated.
This is my code and attempt at changing it into a menu, please let me know what I am doing wrong:
import java.awt.*;
import java.awt.event.*;
import java.io.*;
public class CheesyWP extends Frame implements ActionListener {
/**
* #param args
*/
//new panel for menu
Panel north;
//original
Panel center;
Panel south;
Button save;
Button load;
Button clip;
Button finish;
Menu mn;
MenuItem mSave;
MenuItem mLoad;
MenuItem mClip;
MenuItem mFinish;
TextArea ta;
public static void main(String[] args) {
// TODO Auto-generated method stub
CheesyWP cwp = new CheesyWP();
cwp.doIt();
}
public void doIt() {
center = new Panel();
south = new Panel();
clip = new Button("Open Clipboard");
save = new Button("Save");
load = new Button("Load");
finish = new Button("Finish");
//menu items
north = new Panel();
mn = new Menu();
mSave = new MenuItem("Save");
mLoad = new MenuItem("Load");
mClip = new MenuItem("Open Clipboard");
mFinish = new MenuItem("Finish");
mn.add(mSave);
mn.add(mLoad);
mn.add(mClip);
mn.add(mFinish);
mSave.addActionListener(this);
mLoad.addActionListener(this);
mClip.addActionListener(this);
mFinish.addActionListener(this);
//north.add(mn); <-------//PROBLEM HERE
clip.addActionListener(this);
save.addActionListener(this);
load.addActionListener(this);
finish.addActionListener(this);
ta = new TextArea(20, 80);
center.add(ta);
south.add(load);
south.add(save);
south.add(clip);
south.add(finish);
this.add(center, BorderLayout.CENTER);
this.add(south, BorderLayout.SOUTH);
this.setSize(600, 300);
this.setVisible(true);
}
public void actionPerformed(ActionEvent ae) {
if (ae.getSource() == save) {
try {
File junk = new File("junk.txt");
FileWriter fw = new FileWriter(junk);
fw.write(ta.getText()); // write whole TextArea contents
fw.close();
} catch (IOException ioe) {
}
}// ends if
if (ae.getSource() == load) {
String temp = "";
try {
File junk = new File("junk.txt");
FileReader fr = new FileReader(junk);
BufferedReader br = new BufferedReader(fr);
while ((temp = br.readLine()) != null) {
ta.append(temp + "\n");
}
br.close();
} catch (FileNotFoundException fnfe) {
} catch (IOException ioe) {
}
}
if (ae.getSource() == finish) {
System.exit(0);
}
if(ae.getSource()==clip){
new ClipBoard();
}
}
class ClipBoard extends Frame {
public ClipBoard() { // a constructor
this.setTitle("Clipboard");
this.setLayout(new FlowLayout());
this.add(new TextArea(10, 50));
this.setSize(400, 160);
this.setVisible(true);
}
}
}

I hope this code help you:
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class JMenuTest extends JFrame {
/**
*
*/
private static final long serialVersionUID = 1L;
public JMenuTest() {
JMenuBar menuBar = new JMenuBar();
setJMenuBar(menuBar);
JMenu connectionMenu = new JMenu("Connection");
menuBar.add(connectionMenu);
JMenuItem menuItemConnect = new JMenuItem("Connect");
menuItemConnect.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
System.out.println("Connected");
}
});
connectionMenu.add(menuItemConnect);
JMenuItem menuItemDisconnect = new JMenuItem("Disconnect");
menuItemDisconnect.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
System.out.println("Disconnected");
}
});
connectionMenu.add(menuItemDisconnect);
JMenuItem menuItemExit = new JMenuItem("Exit");
menuItemExit.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
connectionMenu.add(menuItemExit);
JMenu mnNewMenu_1 = new JMenu("New menu");
menuBar.add(mnNewMenu_1);
this.setVisible(true);
this.setSize(300, 300);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
/**
* #param args
*/
public static void main(String[] args) {
new JMenuTest();
}
}