Errors with CustomDialog.java

Question

I've downloaded CustomDialog.java and it compiled without any errors. When I attempt to run the program, I receive the following error:
----jGRASP exec: java CustomDialog
java.lang.NoSuchMethodError: main
Exception in thread "main"
----jGRASP wedge2: exit code for process is 1.
----jGRASP: operation complete.
What could I be doing wrong? I had no problems whatsoever compiling / running the DialogDemo.java file.

Answer 1

Would it compile correctly if there was a main() method problem?
source file can be found here: http://java.sun.com/docs/books/tutorial/uiswing/components/example-swing/CustomDialog.java
and here:
import javax.swing.JOptionPane;
import javax.swing.JDialog;
import javax.swing.JTextField;
import java.beans.*; //property change stuff
import java.awt.*;
import java.awt.event.*;
/* 1.4 example used by DialogDemo.java. */
class CustomDialog extends JDialog
implements ActionListener,
PropertyChangeListener {
private String typedText = null;
private JTextField textField;
private DialogDemo dd;
private String magicWord;
private JOptionPane optionPane;
private String btnString1 = "Enter";
private String btnString2 = "Cancel";
* Returns null if the typed string was invalid;
* otherwise, returns the string as the user entered it.
public String getValidatedText() {
return typedText;
/** Creates the reusable dialog. */
public CustomDialog(Frame aFrame, String aWord, DialogDemo parent) {
super(aFrame, true);
dd = parent;
magicWord = aWord.toUpperCase();
setTitle("Quiz");
textField = new JTextField(10);
//Create an array of the text and components to be displayed.
String msgString1 = "What was Dr. SEUSS's real last name?";
String msgString2 = "(The answer is \"" + magicWord
+ "\".)";
Object[] array = {msgString1, msgString2, textField};
//Create an array specifying the number of dialog buttons
//and their text.
Object[] options = {btnString1, btnString2};
//Create the JOptionPane.
optionPane = new JOptionPane(array,
JOptionPane.QUESTION_MESSAGE,
JOptionPane.YES_NO_OPTION,
null,
options,
options[0]);
//Make this dialog display it.
setContentPane(optionPane);
//Handle window closing correctly.
setDefaultCloseOperation(DO_NOTHING_ON_CLOSE);
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent we) {
* Instead of directly closing the window,
* we're going to change the JOptionPane's
* value property.
optionPane.setValue(new Integer(
JOptionPane.CLOSED_OPTION));
//Ensure the text field always gets the first focus.
addComponentListener(new ComponentAdapter() {
public void componentShown(ComponentEvent ce) {
textField.requestFocusInWindow();
//Register an event handler that puts the text into the option pane.
textField.addActionListener(this);
//Register an event handler that reacts to option pane state changes.
optionPane.addPropertyChangeListener(this);
/** This method handles events for the text field. */
public void actionPerformed(ActionEvent e) {
optionPane.setValue(btnString1);
/** This method reacts to state changes in the option pane. */
public void propertyChange(PropertyChangeEvent e) {
String prop = e.getPropertyName();
if (isVisible()
&& (e.getSource() == optionPane)
&& (JOptionPane.VALUE_PROPERTY.equals(prop) ||
JOptionPane.INPUT_VALUE_PROPERTY.equals(prop))) {
Object value = optionPane.getValue();
if (value == JOptionPane.UNINITIALIZED_VALUE) {
//ignore reset
return;
//Reset the JOptionPane's value.
//If you don't do this, then if the user
//presses the same button next time, no
//property change event will be fired.
optionPane.setValue(
JOptionPane.UNINITIALIZED_VALUE);
if (btnString1.equals(value)) {
typedText = textField.getText();
String ucText = typedText.toUpperCase();
if (magicWord.equals(ucText)) {
//we're done; clear and dismiss the dialog
clearAndHide();
} else {
//text was invalid
textField.selectAll();
JOptionPane.showMessageDialog(
CustomDialog.this,
"Sorry, \"" + typedText + "\" "
+ "isn't a valid response.\n"
+ "Please enter "
+ magicWord + ".",
"Try again",
JOptionPane.ERROR_MESSAGE);
typedText = null;
textField.requestFocusInWindow();
} else { //user closed dialog or clicked cancel
dd.setLabel("It's OK. "
+ "We won't force you to type "
+ magicWord + ".");
typedText = null;
clearAndHide();
/** This method clears the dialog and hides it. */
public void clearAndHide() {
textField.setText(null);
setVisible(false);
}