Develop Reference

Why am I getting an ArrayIndexOutOfBoundsException when I delete JTable row?

I am getting .ArrayIndexOutOfBoundsException when i try to delete a row from my JTable.
Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: -1
at java.util.Vector.elementData(Vector.java:734)
at java.util.Vector.elementAt(Vector.java:477)
at javax.swing.table.DefaultTableModel.getValueAt(DefaultTableModel.java:648)
at Test$1.valueChanged(Test.java:34)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:184)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:164)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:211)
at javax.swing.DefaultListSelectionModel.removeIndexInterval(DefaultListSelectionModel.java:677)
at javax.swing.JTable.tableRowsDeleted(JTable.java:4509)
at javax.swing.JTable.tableChanged(JTable.java:4412)
at javax.swing.table.AbstractTableModel.fireTableChanged(AbstractTableModel.java:296)
at javax.swing.table.AbstractTableModel.fireTableRowsDeleted(AbstractTableModel.java:261)
at javax.swing.table.DefaultTableModel.removeRow(DefaultTableModel.java:463)
at Test$2.actionPerformed(Test.java:39)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
First, I select the row I want to delete and then when I fire the action the delete button it freezes a bit and gives me exception.
Here is my complete code:
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import javax.swing.table.DefaultTableModel;
public class Test extends JFrame{
private static JTable table;
private DefaultTableModel model = new DefaultTableModel();;
private JButton del = new JButton("DELETE");
public Test(){
JPanel pan= new JPanel();
JTextField numeField = new JTextField(30);
model.addColumn("Id");
model.addColumn("Nume");
table = new JTable(model);
JScrollPane pen = new JScrollPane(table);
del.setEnabled(false);
pan.add(pen);
pan.add(numeField);
pan.add(del);
table.getSelectionModel().addListSelectionListener(new ListSelectionListener(){
public void valueChanged(ListSelectionEvent e){
del.setEnabled(true);
numeField.setText(model.getValueAt(table.getSelectedRow(), 1).toString());
}
});
del.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
model.removeRow(table.getSelectedRow());
}
});
Object[] row = {"1","NAME"};
model.addRow(row);
add(pan);
setExtendedState(MAXIMIZED_BOTH);
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
setVisible(true);
}
public static void main(String[] args) throws IOException {
new Test();
}
}
Full stack trace :
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.DefaultTableModel.getValueAt(Unknown Source)
at Test$1.valueChanged(Test.java:34)
at javax.swing.DefaultListSelectionModel.fireValueChanged(Unknown Source)
at javax.swing.DefaultListSelectionModel.fireValueChanged(Unknown Source)
at javax.swing.DefaultListSelectionModel.fireValueChanged(Unknown Source)
at javax.swing.DefaultListSelectionModel.removeIndexInterval(Unknown Source)
at javax.swing.JTable.tableRowsDeleted(Unknown Source)
at javax.swing.JTable.tableChanged(Unknown Source)
at javax.swing.table.AbstractTableModel.fireTableChanged(Unknown Source)
at javax.swing.table.AbstractTableModel.fireTableRowsDeleted(Unknown Source)
at javax.swing.table.DefaultTableModel.removeRow(Unknown Source)
at Test$2.actionPerformed(Test.java:39)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$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)

The problem is not in the ActionListener, the problem is in the ListSelectionListener; when you delete the row, the row that you're deleting no longer exists; if you want to change the selected row, you have to use the new selected row from the event; probably by using getFirstIndex().
You also need to ensure that the row exists, so that when you delete a row, there's still a valid value to select.
In other words, change your ListSelectionListener to this:
table.getSelectionModel().addListSelectionListener(new ListSelectionListener(){
public void valueChanged(ListSelectionEvent e){
int firstIndex = e.getFirstIndex();
if(firstIndex >= 0 && firstIndex < model.getRowCount()) {
del.setEnabled(true);
numeField.setText(model.getValueAt(firstIndex, 1).toString());
} else {
del.setEnabled(false);
}
}
});

Simple Java Calculator Logic

I'm new to programming and I was making a calculator with only 1 textfield.
I need a method which can recognize which string characters from these (+ , - , * , /)
to send the result to a variable and when i click the = button it shows the result.
I have tried to write something like that (1+2) and save it to variable then then when I try to press = button to settext the variable it shows a privilage error.
Here is the code
JButton btnOne = new JButton("1");
btnOne.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sum+=1;
txtoprtn.setText(txtoprtn.getText()+"1");
JButton btnTwo = new JButton("2");
btnTwo.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sum+=2;
txtoprtn.setText(txtoprtn.getText()+"2");
}
});
JButton btnAdd = new JButton("+");
btnAdd.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
txtoprtn.setText(txtoprtn.getText()+"+");
}
});
JButton btnEqual = new JButton("=");
btnEqual.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
x = Integer.parseInt(txtoprtn.getText());
txtoprtn.setText(Integer.toString(x));
}
}
);
and this is the error
**Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: "1+2"
at java.lang.NumberFormatException.forInputString(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at com.jadv.day01.tasks.AdvCalc$11.actionPerformed(AdvCalc.java:140)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$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$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)**
any suggestions????

First problem
When you try to just write a string statement of "1+2", what do you expect will happen? It can't simply just be evaluated like that. You would have to first use Integer.parseInt() to each of your # buttons after the number insertion is done(say, when you click the +/-///*, or =. That means the number is done and you'll get say
Integer.parseInt("123") instead of Integer.parseInt("1")+Integer.parseInt("2")+Integer.parseInt("3")
What you're trying to do is parsing a + in the middle of the parse. Keep the integer parse to the numbers and the operators stored somewhere else(explained in second problem)
Second problem
When you say "+", that doesn't parse into any operation. You would have to store the values into their individual variables and when clicked a + button, you would get a correct answer. If you want to do this without any external imports, then you would have to store the operations in a list and evaluate when = is clicked.
btnAdd.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
operations.add("+");//operations is a list
}
});
Solving both problems at once using an import
If you want to evaluate using a package, then use this:
ScriptEngine evaluationMachine = new ScriptEngineManager().getEngineByName("JavaScript");
engine.eval(foo); //evaluates something like "2+1" into 3.
with the following imports:
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
EDIT: By the way, though the second way is much faster, you should probably try and write it without external imports since you're new to programming. There will be inevitable situations where you're going to have to think about the problem.

The cause of the exception is that you are trying to parse a String like "1+2" to an Integer in the line:
x = Integer.parseInt(txtoprtn.getText());
You should store the numbers somewhere else, i.e. in an ArrayList.

JFileChooser crashes - Java 7

I'm trying to make my program load a txt file with JFileChooser, but it doesn't seem to work. When I press the JButton, the console gives me a lot of errors. Here's the entire code so far:
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.swing.*;
import javax.swing.JFileChooser;
public class Sudoku extends JFrame{
JPanel mainWindow = new JPanel();
JPanel buttonWindow = new JPanel();
JPanel sudokuArea = new JPanel();
JButton load = new JButton("Load");
JButton solve = new JButton("Solve");
JTextArea sudokuGrid = new JTextArea();
Field field = new Field();
public static void main(String[] args) {
new Sudoku();
}
public Sudoku(){
super("SudokuSolver");
setSize(200,300);
setResizable(false);
setDefaultCloseOperation(EXIT_ON_CLOSE);
add(mainWindow);
mainWindow.setLayout(new BorderLayout());
mainWindow.add(buttonWindow, BorderLayout.SOUTH);
mainWindow.add(sudokuArea, BorderLayout.CENTER);
buttonWindow.add(load);
buttonWindow.add(solve);
sudokuArea.setLayout(new BorderLayout());
sudokuArea.add(sudokuGrid, BorderLayout.CENTER);
sudokuGrid.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 12));
sudokuGrid.setEditable(false);
sudokuGrid.append(field.toString());
load.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
loader();
}
public void loader(){
JFileChooser sumtin = new JFileChooser();
if(sumtin.showOpenDialog() == JFileChooser.APPROVE_OPTION)
{
File filer = sumtin.getSelectedFile();
field.fromFile(filer.getName());
sudokuGrid.setText(field.toString());
mainWindow.revalidate();
mainWindow.repaint();
}
}
} );
setVisible(true);
}
The field method is from another class called Field, but it's not really relevant (I think).
Here's what the console says:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at Sudoku$1.loader(Sudoku.java:52)
at Sudoku$1.actionPerformed(Sudoku.java:45)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$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 Sour
ce)
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 Sour
ce)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Sour
ce)
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 Sour
ce)
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)
I'm not really sure what to make of it, as I don't really know what it means. Any pointers?
EDIT: New errorcode after trying David Colers code:
Sudoku.java:49: error: method showOpenDialog in class JFileChooser cannot be app
lied to given types;
if(sumtin.showOpenDialog() == JFileChooser.APPRO
VE_OPTION)
^
required: Component
found: no arguments
reason: actual and formal argument lists differ in length
1 error

you are not handling the JFileChooser correctly for one thing.
EDIT: changed this keyword to null.
JFileChooser sumtin = new JFileChooser();
if(sumtin.showOpenDialog(null) == JFileChooser.APPROVE_OPTION)
{
File filer = sumtin.getSelectedFile();
field.fromFile(filer.getName());
sudokuGrid.setText(field.toString());
mainWindow.revalidate();
mainWindow.repaint();
}

you missed a few steps:
first create a filechooser
JFileChooser fileChooser = new JFileChooser();
show it, and get the result
int result = fileChooser.showOpenDialog(this);
And if the user has opened a file, you can get it and do what you want
if (result == JFileChooser.APPROVE_OPTION) {
File file = fileChooser.getSelectedFile();
...
}

NumberFormatException while using JFrame

The code is supposed to get an order and its price and save them in their respective ArrayLists.
public class SetMenu0{
private double price;
private int size;
private String output;
private String priceOutput;
String next;
JTextField orderIn;
JTextField priceIn;
private JFrame orderInput;
JPanel txtFldPanel;
JPanel btnPanel;
ArrayList orderList = new ArrayList<String>();
ArrayList priceList = new ArrayList<Double>();
public SetMenu0()
{
orderInput = new JFrame();
orderInput.setTitle("Input Order and Price");
orderInput.setSize(200,350);
orderInput.getContentPane();
orderInput.setLayout(new BorderLayout());
orderInput.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel txtFldPanel = new JPanel();
orderIn = new JTextField(10);
priceIn = new JTextField(5);
txtFldPanel.add(orderIn);
txtFldPanel.add(priceIn);
JPanel btnPanel = new JPanel();
JButton addBtn = new JButton("ADD");
btnPanel.add(addBtn);
addBtn.addActionListener(new ButtonListener());
addBtn.setActionCommand("add");
JButton fnshBtn = new JButton("FINISH");
btnPanel.add(fnshBtn);
addBtn.addActionListener(new ButtonListener());
fnshBtn.setActionCommand("fnsh");
size = orderList.size();
Container cont = orderInput.getContentPane();
cont.add(txtFldPanel,BorderLayout.NORTH);
cont.add(btnPanel,BorderLayout.SOUTH);
orderInput.pack();
}
private class ButtonListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
String actionEnter = e.getActionCommand();
if(actionEnter.equals("add"))
{
orderList.add(orderIn.getText());
priceList.add(Double.parseDouble(priceIn.getText()));
orderIn.setText("");
priceIn.setText("");
}
else if(actionEnter.equals("fnsh"))
{
orderInput.dispose();
}
}
}
public JFrame getFrame()
{
return orderInput;
}
public ArrayList getOrd()
{
return orderList;
}
public ArrayList getPri()
{
return priceList;
}
public int getSize()
{
return size;
}
}
When i press the ADD button it shows a NumberFormatException. Why is this? I could add the rest of the code from the main but why is it not saving in the ArrayList?
This is the error:
java.lang.NumberFormatException: For input string: ""
at java.lang.NumberFormatException.forInputString(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at com.howtodoinjava.demo.poi.SetMenu0$ButtonListener.actionPerformed(SetMenu0.java:84)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$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$400(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)

It's probably due to this line:
priceList.add(Double.parseDouble(priceIn.getText()));
You want to make sure that priceIn text field contains a number before you try to parse the text.

You have to use (on button add click)
if(!(priceIn.isEmpty || orderIn.isEmpty)){
//Do your adding
}
This code checks if there is something in the JTextFiels

Java Display message issue

I have a java program that creates a JFrame like this:
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
gui.setFrame(new gui(), 1000, 300);
}
});
I also have a class (gui.java) that implements setFrame:
public static void setFrame(final JFrame frame, final int width, final int height) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
f1=frame;
frame.setTitle("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(width, height);
frame.setVisible(true);
}
});
}
If the user tries to click Submit (a button I created) and the fields in the JFrame are not filled in then it throws an error. The code for the error message is:
submit.addMouseListener(new MouseListener(){
#Override
public void mouseClicked(MouseEvent e) {}
#Override
public void mouseEntered(MouseEvent e) {}
#Override
public void mouseExited(MouseEvent e) {}
#Override
public void mousePressed(MouseEvent e) {}
#Override
public void mouseReleased(MouseEvent e) {
//check to make sure all values filled in
if(chooser.getSelectedFile().toString()!=null&&saveChooser.getSelectedFile().toString()!=null)
parseFile.readFile(chooser.getSelectedFile(),saveChooser.getSelectedFile(),startSpanText.getText(),(String)col2.getSelectedItem(),(String)col3.getSelectedItem(),(String)col4.getSelectedItem(),(String)col5.getSelectedItem(),(String)col6.getSelectedItem());
else
JOptionPane.showMessageDialog(f1,"Bad");
}
});
//Note: f1 is a static version of the frame I initially received
The error I get is:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at gui$3.mouseReleased(gui.java:133)
at java.awt.AWTEventMulticaster.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$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.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)
What did I do wrong?

One of the variables is null. It could be:
chooser
chooser.getSelectedFile()
saveChooser
saveChooser.getSelectedFile()
parseFile
startSpanText
col2 to col6
Use the line number in the stack trace, and a debugger or traces in the code to know which one. My guess would be one of the selected files, since it makes no sense to call
chooser.getSelectedFile().toString() != null
Either there is no selected file, and it throws an NPE because getSelectedFile() returns null, or there is one, and its toString() will never be null.
Also, you shouldn't use a mouse listener to do something when a button is pressed. That's what an ActionListener is for. It will be simpler, and also work when the user presses the button with its keyboard.

Your exception message should point you to the answer. One of the items you are using in your mouseReleased method is null:
#Override
public void mouseReleased(MouseEvent e) {
//check to make sure all values filled in
if(chooser.getSelectedFile().toString()!=null &&
saveChooser.getSelectedFile().toString()!=null)
parseFile.readFile(chooser.getSelectedFile(), saveChooser.getSelectedFile(),
startSpanText.getText(), (String)col2.getSelectedItem(),
(String)col3.getSelectedItem(), (String)col4.getSelectedItem(),
(String)col5.getSelectedItem(), (String)col6.getSelectedItem());
else
JOptionPane.showMessageDialog(f1,"Bad");
}
Use a debugger to inspect which variables are set. Use the line number in the exception message to help you.