Develop Reference

JTable addRow does not work with an actionListner

I'm basically building a simple GUI for a simple baking program.
The problem is that after creating a model for JTable, adding a row of data
model.addRow(new String[] {"data", "data","data", "data"});
does not work inside of an actionlistener:
public void actionPerformed(ActionEvent event) {
String buttonText = event.getActionCommand();
if (buttonText.equals("Create Savings Account")) {
createSavingsAccount();
public void createCreditAccount() {
logic.createCreditAccount(pNrField.getText());
model.addRow(new String[] {"data", "data","data", "data"});
}
If I try to create an account I get this message:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at svimag6.GUImain.createSavingsAccount(GUImain.java:145)
at svimag6.GUImain.actionPerformed(GUImain.java:124)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at svimag6.GUImain.createSavingsAccount(GUImain.java:145)
at svimag6.GUImain.actionPerformed(GUImain.java:124)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at svimag6.GUImain.createCreditAccount(GUImain.java:140)
at svimag6.GUImain.actionPerformed(GUImain.java:128)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at svimag6.GUImain.createCreditAccount(GUImain.java:140)
at svimag6.GUImain.actionPerformed(GUImain.java:128)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
However, if I hardcode the adding of new rows into the table, (in the constructor) it works. But I can't add data dynamically.
Here's the code:
package gui;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;
import java.awt.event.*;
import java.awt.*;
//YOU NEED TO ADD A FIELD in the GUI FOR NAME, LASTNAME AND PNR
public class GUImain extends JFrame implements ActionListener {
private static final long serialVersionUID = 1L;
private BankLogic logic;
private JList<Object> customerList;
private JTable accountTable;
private JTable transactionTable;
private JTextField nameField;
private JTextField lastnameField;
private JTextField pNrField;
private DefaultTableModel model;
private DefaultTableModel model1;
private JButton addButton = new JButton("Add Customer");
private JButton showButton = new JButton("Show");
private JButton clearButton = new JButton("Rensa");
private JButton createSavingsAccountButton = new JButton("Create Savings Account");
private JButton createCreditAccountButton = new JButton("Create Credit Account");
private JButton deleteAccountButton = new JButton("Delete Account");
private JButton withdrawButton = new JButton("Withdraw");
private JButton depositButton = new JButton("Deposit");
String[] accountColumns = { "ID", "Account Type", "Balance", "Interest" };
String[] transactionColumns = { "Date", "Time", "Amount", "Balance" };
String testdata[][] = { { "101", "Amit", "670000" }, { "102", "Jai", "780000" }, { "101", "Sachin", "700000" } };
public GUImain() {
initiateInstanceVariables();
buildFrame();
}
private void initiateInstanceVariables() {
logic = new BankLogic();
customerList = new JList<Object>();
accountTable = new JTable();
DefaultTableModel model = new DefaultTableModel(0, 0);
model.setColumnIdentifiers(accountColumns);
accountTable.setModel(model);
transactionTable = new JTable();
DefaultTableModel model1 = new DefaultTableModel(0, 0);
model1.setColumnIdentifiers(transactionColumns);
transactionTable.setModel(model1);
model.addRow(new String[] {"data", "data","data", "data"});
nameField = new JTextField();
lastnameField = new JTextField();
pNrField = new JTextField();
nameField.setBorder(BorderFactory.createTitledBorder("Name"));
lastnameField.setBorder(BorderFactory.createTitledBorder("Lastname"));
pNrField.setBorder(BorderFactory.createTitledBorder("pNr"));
}
private void buildFrame() {
setTitle("Bank");
setSize(300, 250);
setLayout(new GridLayout(1, 2));
JPanel bankpanel = new JPanel(new GridLayout(5, 1));
bankpanel.add(nameField);
bankpanel.add(lastnameField);
bankpanel.add(pNrField);
bankpanel.add(addButton);
bankpanel.add(showButton);
bankpanel.add(clearButton);
bankpanel.add(createSavingsAccountButton);
bankpanel.add(createCreditAccountButton);
createSavingsAccountButton.setVisible(false);
createCreditAccountButton.setVisible(false);
addButton.addActionListener(this);
showButton.addActionListener(this);
clearButton.addActionListener(this);
createSavingsAccountButton.addActionListener(this);
createCreditAccountButton.addActionListener(this);
deleteAccountButton.addActionListener(this);
// // ACCOUNT TABLE
accountTable.setCellSelectionEnabled(true);
ListSelectionModel select = accountTable.getSelectionModel();
select.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
// // ACCOUNT TABLE
add(bankpanel);
add(customerList);
add(new JScrollPane(accountTable), BorderLayout.CENTER);
add(new JScrollPane(transactionTable), BorderLayout.CENTER);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
// UI LOGIC. This activated the functions below.
public void actionPerformed(ActionEvent event) {
String buttonText = event.getActionCommand();
if (buttonText.equals("Add Customer")) {
addCustomer();
showAccountButtons();
}
if (buttonText.equals("Show")) {
showSelected();
}
if (buttonText.equals("Clear")) {
clear();
}
if (buttonText.equals("Create Savings Account")) {
createSavingsAccount();
}
if (buttonText.equals("Create Credit Account")) {
createCreditAccount();
}
}
private void addCustomer() {
logic.createCustomer(nameField.getText(), lastnameField.getText(), pNrField.getText());
customerList.setListData(logic.getAllCustomers().toArray());
clear();
}
public void createCreditAccount() {
logic.createCreditAccount(pNrField.getText());
model.addRow(new String[] {"data", "data","data", "data"});
}
public void createSavingsAccount() {
logic.createSavingsAccount(pNrField.getText());
model.addRow(new String[] {"data", "data","data", "data"});
}
private void showSelected() {
int position = customerList.getSelectedIndex();
if (position > -1) {
nameField.setText(logic.getNameForPersonAt(position));
lastnameField.setText(logic.getLastNameForPersonAt(position));
pNrField.setText(logic.getpNrAt(position));
} else {
JOptionPane.showMessageDialog(null, "You need a person in the list!");
}
}
private void showAccountButtons() {
createSavingsAccountButton.setVisible(true);
createCreditAccountButton.setVisible(true);
}
private void clear() {
nameField.setText("");
lastnameField.setText("");
pNrField.setText("");
}
}

You have "shadowed variables".
You try to define instance variables but they are null:
private DefaultTableModel model;
private DefaultTableModel model1;
And then you create a local variable which is not null
DefaultTableModel model = new DefaultTableModel(0, 0);
...
DefaultTableModel model1 = new DefaultTableModel(0, 0);
The ActionListener can only access the instance variable but it is null so you get a NPE.
Get rid of the local variables:
model = new DefaultTableModel(0, 0);
...
model1 = new DefaultTableModel(0, 0);

Why does MouseListener on JTableHeader throw ArrayIndexOutOfBoundsException?

I'm just starting out with swing, but I've been stuck on this issue for about a week and I've tried everything I can think. I'm trying to update the table model as the result of a click on a column header and getting an ArrayIndexOutOfBoundsException.
I've simplified the code here, but can someone please explain why this:
package gradebook.model.courseTable;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.table.DefaultTableModel;
public class CourseTableTest extends JTable {
public static void main(String[] args){
SwingUtilities.invokeLater(new Runnable(){
public void run(){
JFrame frame = new JFrame();
frame.add(new JScrollPane(new CourseTable()));
frame.setVisible(true);
frame.pack();
frame.setLocationRelativeTo(null);
}
});
}
public CourseTableTest(){
super(3, 3);
this.tableHeader.addMouseListener(new MouseAdapter() {
public void mousePressed(MouseEvent e) {
setModel(new DefaultTableModel(3, 3));
}
});
}
}
throws this when clicked?:
Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: -1
at java.util.Vector.elementData(Unknown Source)
at java.util.Vector.elementAt(Unknown Source)
at javax.swing.table.DefaultTableColumnModel.getColumn(Unknown Source)
at javax.swing.JTable.getCellRenderer(Unknown Source)
at javax.swing.plaf.basic.BasicTableUI.paintCell(Unknown Source)
at javax.swing.plaf.basic.BasicTableUI.paintDraggedArea(Unknown Source)
at javax.swing.plaf.basic.BasicTableUI.paintCells(Unknown Source)
at javax.swing.plaf.basic.BasicTableUI.paint(Unknown Source)
at javax.swing.plaf.ComponentUI.update(Unknown Source)
at javax.swing.JComponent.paintComponent(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintToOffscreen(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
at javax.swing.RepaintManager.paint(Unknown Source)
at javax.swing.JComponent._paintImmediately(Unknown Source)
at javax.swing.JComponent.paintImmediately(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.access$700(Unknown Source)
at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$000(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: -1
at java.util.Vector.elementData(Unknown Source)
at java.util.Vector.elementAt(Unknown Source)
at javax.swing.table.DefaultTableColumnModel.getColumn(Unknown Source)
at javax.swing.JTable.getCellRenderer(Unknown Source)
at javax.swing.plaf.basic.BasicTableUI.paintCell(Unknown Source)
at javax.swing.plaf.basic.BasicTableUI.paintDraggedArea(Unknown Source)
at javax.swing.plaf.basic.BasicTableUI.paintCells(Unknown Source)
at javax.swing.plaf.basic.BasicTableUI.paint(Unknown Source)
at javax.swing.plaf.ComponentUI.update(Unknown Source)
at javax.swing.JComponent.paintComponent(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintToOffscreen(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
at javax.swing.RepaintManager.paint(Unknown Source)
at javax.swing.JComponent._paintImmediately(Unknown Source)
at javax.swing.JComponent.paintImmediately(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.access$700(Unknown Source)
at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$000(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Edit
Some of you have asked why I would change the model during a click of the column header. In my application, the table columns represent a school assignment. When the header is clicked it opens a dialog box that allows the user to either modify or delete the assignment. If the user clicks delete I would like to remove the column from the table. But any time I try to change the table structure within the click handler I get this error.

The MouseListener must be doing some processing and doesn't like you changing the data in the middle of the processing.
Try:
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
setModel(new DefaultTableModel(3, 3));
}
});
This will let the MouseListener code finish executing before you change the model.
The real question is why would you change the model when you click on the header?
Edit:
As noted by MadProgrammer the first suggestion doesn't work.
As another hack if you are just trying to clear the data in the model you can use:
#Override
public void mousePressed(MouseEvent e)
{
model.setRowCount(0);
model.setRowCount(3);
}
If you want a table with a completely different structure then I would suggest you do something like:
#Override
public void mousePressed(MouseEvent e)
{
scrollPane.setViewportView( new JTable(4, 4) );
}

Sorted JTable's data refresh gives exception in java : Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException

I try to make Test code about JTable input and refresh.
Insert and delete is working well,
but if I delete or insert data after sort the table, it make's exception:
"AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException : 9>=0" ..
Here's my test code.
How do I fix it?
and.. any other advice?
public class Test extends JFrame{
private DefaultTableModel modelTest = new DefaultTableModel();
private JTable tableTest = new JTable(modelTest);
private JScrollPane paneTest = new JScrollPane(tableTest);
private JButton button1 = new JButton("pattern1");
private JButton button2 = new JButton("pattern2");
private JButton button3 = new JButton("delete");
private void compInit(){
paneTest.setBounds(0, 0,778, 300);
button1.setBounds(250, 320,80,20);
button2.setBounds(450,320,80,20);
button3.setBounds(300,400,80,20);
DefaultTableModel tmp = modelTest;
tmp.addColumn(" ");
tmp.addColumn("col1");
tmp.addColumn("col2");
tmp.addColumn("col3");
tmp.addColumn("col4");
tmp.addColumn("col5");
tmp.addColumn("col6");
tmp.addColumn("col7");
try {
tableTest.setDefaultRenderer(Class.forName("java.lang.String"), new DefaultTableCellRenderer());
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
tableTest.setAutoCreateRowSorter(true);
tableTest.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
tableTest.getColumnModel().getColumn(0).setPreferredWidth(20);
tableTest.getColumnModel().getColumn(1).setPreferredWidth(45);
tableTest.getColumnModel().getColumn(2).setPreferredWidth(110);
tableTest.getColumnModel().getColumn(3).setPreferredWidth(60);
tableTest.getColumnModel().getColumn(4).setPreferredWidth(100);
tableTest.getColumnModel().getColumn(5).setPreferredWidth(227);
tableTest.getColumnModel().getColumn(6).setPreferredWidth(100);
tableTest.getColumnModel().getColumn(7).setPreferredWidth(100);
tableTest.getTableHeader().setForeground(new Color(105,105,105));
this.add(button1);
this.add(button2);
this.add(button3);
this.add(paneTest);
}
private void pattern1(){
for(int i = 0;i<10;i++){
Vector rowData = new Vector<>();
rowData.add(false);
rowData.add(i+1);
rowData.add("a : " + i);
rowData.add("b : " + i);
rowData.add("c : " + i);
rowData.add("d : " + i);
rowData.add("e : " + i);
rowData.add("f : " + i);
modelTest.addRow(rowData);
}
}
private void pattern2(){
for(int i = 0;i<10;i++){
Vector rowData = new Vector<>();
rowData.add(false);
rowData.add(i+1);
rowData.add("z : " + i);
rowData.add("y : " + i);
rowData.add("x : " + i);
rowData.add("w : " + i);
rowData.add("v : " + i);
rowData.add("u : " + i);
modelTest.addRow(rowData);
}
}
private void delete(){
DefaultTableModel tmp = modelTest;
tmp.getDataVector().removeAllElements();
tableTest.repaint();
}
private void eventInit(){
button1.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
pattern1();
}
});
button2.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
pattern2();
}
});
button3.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
delete();
}
});
}
public Test(){
this.setLayout(null);
this.compInit();
this.eventInit();
this.setSize(778, 500);
this.setLocationRelativeTo(null);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.setVisible(true);
}
public static void main(String[] ar){
SwingUtilities.invokeLater(new Runnable(){
public void run(){
new Test();
}
});
}
}
Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: 3 >= 1
at java.util.Vector.elementAt(Unknown Source)
at javax.swing.table.DefaultTableModel.getValueAt(Unknown Source)
at javax.swing.table.TableRowSorter$TableRowSorterModelWrapper.getValueAt(Unknown Source)
at javax.swing.table.TableRowSorter$TableRowSorterModelWrapper.getStringValueAt(Unknown Source)
at javax.swing.DefaultRowSorter.compare(Unknown Source)
at javax.swing.DefaultRowSorter.access$100(Unknown Source)
at javax.swing.DefaultRowSorter$Row.compareTo(Unknown Source)
at javax.swing.DefaultRowSorter$Row.compareTo(Unknown Source)
at java.util.Arrays.binarySearch0(Unknown Source)
at java.util.Arrays.binarySearch(Unknown Source)
at javax.swing.DefaultRowSorter.insertInOrder(Unknown Source)
at javax.swing.DefaultRowSorter.rowsInserted0(Unknown Source)
at javax.swing.DefaultRowSorter.rowsInserted(Unknown Source)
at javax.swing.JTable.notifySorter(Unknown Source)
at javax.swing.JTable.sortedTableChanged(Unknown Source)
at javax.swing.JTable.tableChanged(Unknown Source)
at javax.swing.table.AbstractTableModel.fireTableChanged(Unknown Source)
at javax.swing.table.AbstractTableModel.fireTableRowsInserted(Unknown Source)
at javax.swing.table.DefaultTableModel.insertRow(Unknown Source)
at javax.swing.table.DefaultTableModel.addRow(Unknown Source)
at timer.Test.pattern1(Test.java:77)
at timer.Test.access$0(Test.java:66)
at timer.Test$1.actionPerformed(Test.java:106)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at javax.swing.DefaultRowSorter.getViewToModelAsInts(Unknown Source)
at javax.swing.DefaultRowSorter.rowsInserted0(Unknown Source)
at javax.swing.DefaultRowSorter.rowsInserted(Unknown Source)
at javax.swing.JTable.notifySorter(Unknown Source)
at javax.swing.JTable.sortedTableChanged(Unknown Source)
at javax.swing.JTable.tableChanged(Unknown Source)
at javax.swing.table.AbstractTableModel.fireTableChanged(Unknown Source)
at javax.swing.table.AbstractTableModel.fireTableRowsInserted(Unknown Source)
at javax.swing.table.DefaultTableModel.insertRow(Unknown Source)
at javax.swing.table.DefaultTableModel.addRow(Unknown Source)
at timer.Test.pattern2(Test.java:92)
at timer.Test.access$1(Test.java:81)
at timer.Test$2.actionPerformed(Test.java:111)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

Whenever you change your model vector directly, make sure to notify the container about this. You fail to do that in the following method:
private void delete(){
DefaultTableModel tmp = modelTest;
tmp.getDataVector().removeAllElements();
tableTest.repaint();
}
After the removeAllElements() you should call tmp.fireTableDataChanged(). Something like:
private void delete(){
DefaultTableModel tmp = modelTest;
tmp.getDataVector().removeAllElements();
tmp.fireTableDataChanged();
tableTest.repaint();
}
Reason: Changes directly to the Model's underlying data vector are not automatically propagated to the View. You are changing a Vector this way, not a Model. Changes to the Model are propagated to the View. Your calls to Model.addRow() inform the View that a row was added. Your Vector.removeAllElements() call is not informed to the View so after that call View and Model are out of sync (that is, if they weren't both empty before). The call to Model.fireTableDataChanged informs the View that the whole table data in the Model has changed. After this call they are in sync again. When Model and View are out of sync, you can expect ArrayOutOfBoundException's to occur e.g. during sorting.

I also had this problem recently - a NullPointerException caused by DefaultRowSorter.getViewToModelAsInts.
The problem for me is that I was trying to directly update the GUI when an exception was thrown in SwingWorker's doInBackground() method. I found the exact solution to my particular problem here. Maybe that will help you or at least point you in the right direction as I wouldn't be surprised if your problem was because you are trying to manipulate the GUI from the wrong thread.

NullPointerException while opening new frame

today I'm having a bit of a slight, see, I'm trying to run my code and I'm getting a NullPointerException. The clues in the exception leads me to this function right here:
private void irGuiJuego(JFrame frame){
SwingConsole.run(new GUIJuego(), 800, 600, true);
frame.dispose();
}
Where SwingConsole would have this code:
package utiles;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
public class SwingConsole {
public static void run(final JFrame frame, final int width, final int height, final boolean exitOnClose) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
if (exitOnClose)
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(width, height);
//frame.setResizable(false);
frame.setVisible(true);
}
});
}
public static void run(final JFrame frame, final int width, final int height, final boolean exitOnClose, final String title) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
if (exitOnClose)
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setTitle(title);
frame.setSize(width, height);
frame.setVisible(true);
}
});
}
}
It is kind of odd, considering that I'm using the same method to open up another frame, in this function to be specific:
private void volverMenuInicio(JFrame frame){
SwingConsole.run(new MenuInicio(), 300, 150, true);
frame.dispose();
}
I'll leave you guys a pastebin of the GUIJuego Frame, since it's sort of excessive to post it here: http://pastebin.com/LSXbc7KE , have the pastebin of the other frame too, in case you need it: http://pastebin.com/hbdd7j84
Edit: Here's the stacktrace, sorry for the lack of it before!
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at java.awt.Container.addImpl(Unknown Source) at
java.awt.Container.add(Unknown Source) at
gui.GUIJuego.(GUIJuego.java:113) at
gui.MenuNuevoJuego.irGuiJuego(MenuNuevoJuego.java:95) at
gui.MenuNuevoJuego.access$2(MenuNuevoJuego.java:94) at
gui.MenuNuevoJuego$2.actionPerformed(MenuNuevoJuego.java:74) at
javax.swing.AbstractButton.fireActionPerformed(Unknown Source) at
javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source) at
javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source) at
javax.swing.DefaultButtonModel.setPressed(Unknown Source) at
javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown
Source) at java.awt.Component.processMouseEvent(Unknown Source) at
javax.swing.JComponent.processMouseEvent(Unknown Source) at
java.awt.Component.processEvent(Unknown Source) at
java.awt.Container.processEvent(Unknown Source) at
java.awt.Component.dispatchEventImpl(Unknown Source) at
java.awt.Container.dispatchEventImpl(Unknown Source) at
java.awt.Component.dispatchEvent(Unknown Source) at
java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source) at
java.awt.LightweightDispatcher.processMouseEvent(Unknown Source) at
java.awt.LightweightDispatcher.dispatchEvent(Unknown Source) at
java.awt.Container.dispatchEventImpl(Unknown Source) at
java.awt.Window.dispatchEventImpl(Unknown Source) at
java.awt.Component.dispatchEvent(Unknown Source) at
java.awt.EventQueue.dispatchEventImpl(Unknown Source) at
java.awt.EventQueue.access$200(Unknown Source) at
java.awt.EventQueue$3.run(Unknown Source) at
java.awt.EventQueue$3.run(Unknown Source) at
java.security.AccessController.doPrivileged(Native Method) at
java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown
Source) at
java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown
Source) at java.awt.EventQueue$4.run(Unknown Source) at
java.awt.EventQueue$4.run(Unknown Source) at
java.security.AccessController.doPrivileged(Native Method) at
java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown
Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at
java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown
Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at
java.awt.EventDispatchThread.run(Unknown Source)
Thanks for reading, by the way!

The NPE is being thrown from line 113 in GUIJuego.java, as the stack trace indicates:
panelDatosCiudad.add(arcaLabel);
It's happening because arcaLabel, defined in line 35, is never set to a value, and so you're adding a null JLabel to the container.

Unknown exception in custom JButton, in java (swing)

I have tried to create a custom JButton. I tried to paint its caption via the paintComponent method but i did not like the font rendering of this method. So I added a JLabel to my button which worked fine in first place but after removing the parts for the paintString stuff the compiler throws errors i do not know how to fix/solve. Also what can I improve?
The JButtons code:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.Rectangle2D;
class myImageButton extends JButton implements MouseListener {
private Color fontColor = new Color(0x222);
private Image btn = Toolkit.getDefaultToolkit().getImage("btn.png");
private Image btnHvr = Toolkit.getDefaultToolkit().getImage("btnhvr.png");
private Image btnDwn = Toolkit.getDefaultToolkit().getImage("btndwn.png");
private Image fallback = btn;
private Image currentImage = btn;
private JFrame parent;
private JLabel label;
private boolean mouseDown = false;
private int captionWidth;
private int captionHeight;
private Font font = new Font("Open Sans", Font.PLAIN, 12);
private FontMetrics fm = new FontMetrics(font) { };
myImageButton(String text, JFrame parent) {
parent = parent;
Rectangle2D bounds = fm.getStringBounds(text, null);
captionWidth = (int) bounds.getWidth();
captionHeight = (int) bounds.getHeight();
addMouseListener(this);
setBounds(0,0,79,28);
setFont(font);
label = new JLabel(text);
this.add(label);
}
public void paintComponent(Graphics g) {
g.setColor(parent.getBackground());
g.fillRect(0,0,getWidth(),getHeight());
g.drawImage(currentImage,0,0,parent);
//g.setColor(fontColor);
//g.drawString(caption, getWidth() / 2 - captionWidth / 2, getHeight() / 2 + captionHeight / 3);
}
public void paintBorder(Graphics g) {
}
public void mousePressed(MouseEvent e) {
//mouse down
currentImage = btnDwn;
mouseDown = true;
repaint();
}
public void mouseReleased(MouseEvent e) {
//mouse up
currentImage = btnHvr;
mouseDown = false;
repaint();
}
public void mouseEntered(MouseEvent e) {
//hover on
if (mouseDown) {
currentImage = btnDwn;
} else {
currentImage = btnHvr;
}
repaint();
}
public void mouseExited(MouseEvent e) {
//hover off
if (mouseDown) {
currentImage = btnDwn;
} else {
currentImage = btn;
}
repaint();
}
public void mouseClicked(MouseEvent e) {
//click
//should be managed by parent UI class
}
}
The JFrames code:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Launch {
public static void main (String[]args) {
JFrame jf = new JFrame();
myImageButton cp = new myImageButton("Exit", jf);
jf.setLayout(null);
jf.setSize(640,480);
jf.setResizable(false);
jf.setLocationRelativeTo(null);
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jf.add(cp);
cp.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
myImageButton_ActionPerformed(evt);
}
});
cp.setLocation(50,50);
jf.setVisible(true);
}
public static void myImageButton_ActionPerformed(ActionEvent evt) {
System.out.println("Click");
}
}
The full exception stackTrace:
Starte C:\Users\Selim\Desktop\Launch.java
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at myImageButton.paintComponent(myImageButton.java:38)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JLayeredPane.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paintToOffscreen(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
at javax.swing.RepaintManager.paint(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at java.awt.GraphicsCallback$PaintCallback.run(Unknown Source)
at sun.awt.SunGraphicsCallback.runOneComponent(Unknown Source)
at sun.awt.SunGraphicsCallback.runComponents(Unknown Source)
at java.awt.Container.paint(Unknown Source)
at java.awt.Window.paint(Unknown Source)
at javax.swing.RepaintManager$3.run(Unknown Source)
at javax.swing.RepaintManager$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.access$1000(Unknown Source)
at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at myImageButton.paintComponent(myImageButton.java:38)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JLayeredPane.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paintToOffscreen(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
at javax.swing.RepaintManager.paint(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at java.awt.GraphicsCallback$PaintCallback.run(Unknown Source)
at sun.awt.SunGraphicsCallback.runOneComponent(Unknown Source)
at sun.awt.SunGraphicsCallback.runComponents(Unknown Source)
at java.awt.Container.paint(Unknown Source)
at java.awt.Window.paint(Unknown Source)
at javax.swing.RepaintManager$3.run(Unknown Source)
at javax.swing.RepaintManager$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.access$1000(Unknown Source)
at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at myImageButton.paintComponent(myImageButton.java:38)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JLayeredPane.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paintToOffscreen(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
at javax.swing.RepaintManager.paint(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at java.awt.GraphicsCallback$PaintCallback.run(Unknown Source)
at sun.awt.SunGraphicsCallback.runOneComponent(Unknown Source)
at sun.awt.SunGraphicsCallback.runComponents(Unknown Source)
at java.awt.Container.paint(Unknown Source)
at java.awt.Window.paint(Unknown Source)
at javax.swing.RepaintManager$3.run(Unknown Source)
at javax.swing.RepaintManager$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.access$1000(Unknown Source)
at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at myImageButton.paintComponent(myImageButton.java:38)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintToOffscreen(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
at javax.swing.RepaintManager.paint(Unknown Source)
at javax.swing.JComponent._paintImmediately(Unknown Source)
at javax.swing.JComponent.paintImmediately(Unknown Source)
at javax.swing.RepaintManager$3.run(Unknown Source)
at javax.swing.RepaintManager$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.access$1000(Unknown Source)
at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at myImageButton.paintComponent(myImageButton.java:38)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintToOffscreen(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
at javax.swing.RepaintManager.paint(Unknown Source)
at javax.swing.JComponent._paintImmediately(Unknown Source)
at javax.swing.JComponent.paintImmediately(Unknown Source)
at javax.swing.RepaintManager$3.run(Unknown Source)
at javax.swing.RepaintManager$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.access$1000(Unknown Source)
at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at myImageButton.paintComponent(myImageButton.java:38)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintToOffscreen(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
at javax.swing.RepaintManager.paint(Unknown Source)
at javax.swing.JComponent._paintImmediately(Unknown Source)
at javax.swing.JComponent.paintImmediately(Unknown Source)
at javax.swing.RepaintManager$3.run(Unknown Source)
at javax.swing.RepaintManager$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.access$1000(Unknown Source)
at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at myImageButton.paintComponent(myImageButton.java:38)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintToOffscreen(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
at javax.swing.RepaintManager.paint(Unknown Source)
at javax.swing.JComponent._paintImmediately(Unknown Source)
at javax.swing.JComponent.paintImmediately(Unknown Source)
at javax.swing.RepaintManager$3.run(Unknown Source)
at javax.swing.RepaintManager$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.access$1000(Unknown Source)
at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Thanks in advance!
Selim

The problem is here in the constructor of myImageButton:
parent = parent;
The local parent JFrame reference is assigned to itself. Subsequently in paintComponent, the class member variable parent is null producing an NPE. You want
this.parent = parent;
Also what can I improve?
Don't use null layout, always use a layout manager
The JButton component already offers the functionality provided by the custom button by using the following methods: setBorder, setPressedIcon, setRollOverIcon
Follow Java naming conventions. Classes start with an uppercase letter such as MyImageButton

It looks like you are trying to center the text on top of the button icon. The API handles this:
button.setHorizontalTextPosition(JButton.CENTER);
button.setVerticalTextPosition(JButton.CENTER);
The API also handles different icons. Check the API for any method with "Icon" in the method name.