Question 2: Identify the output of the following Java code. Justify the syntax.

File Name:ColorCheckBoxWindow.java (it can be downloaded from Moodle under Week 8 Lecture 8 T322 Resources)

import javax.swing.*;

import java.awt.*;

import java.awt.event.*;

public class ColorCheckBoxWindow extends JFrame

{

private JLabel messageLabel;

private JCheckBox yellowCheckBox;

private JCheckBox redCheckBox;

private final int WINDOW_WIDTH = 300;

private final int WINDOW_HEIGHT = 100;

public ColorCheckBoxWindow()

{

setTitle("Color Check Boxes");

setSize(WINDOW_WIDTH, WINDOW_HEIGHT);

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

messageLabel = new JLabel("Select the check " +

"boxes to change colors.");

yellowCheckBox = new JCheckBox("Yellow background");

redCheckBox = new JCheckBox("Red foreground");

yellowCheckBox.addItemListener(new CheckBoxListener());

redCheckBox.addItemListener(new CheckBoxListener());

setLayout(new FlowLayout());

add(messageLabel);

add(yellowCheckBox);

add(redCheckBox);

setVisible(true);

}

private class CheckBoxListener implements ItemListener

{

public void itemStateChanged(ItemEvent e)

{

if (e.getSource() == yellowCheckBox)

{

if (yellowCheckBox.isSelected())

{

getContentPane().setBackground(Color.yellow);

yellowCheckBox.setBackground(Color.yellow);

redCheckBox.setBackground(Color.yellow);

}

else

{

getContentPane().setBackground(Color.lightGray);

yellowCheckBox.setBackground(Color.lightGray);

redCheckBox.setBackground(Color.lightGray);

}

}

else if (e.getSource() == redCheckBox)

{

if (redCheckBox.isSelected())

{

messageLabel.setForeground(Color.red);

yellowCheckBox.setForeground(Color.red);

redCheckBox.setForeground(Color.red);

}

else

{

messageLabel.setForeground(Color.black);

yellowCheckBox.setForeground(Color.black);

redCheckBox.setForeground(Color.black);

}

}

}

}

public static void main(String[] args)

{

new ColorCheckBoxWindow();

}

}

File Name:ColorWindow.java

import javax.swing.*;

import java.awt.*;

import java.awt.event.*;

public class ColorWindow extends JFrame

{

private JLabel messageLabel;

private JButton redButton;

private JButton blueButton;

private JButton yellowButton;

private JPanel panel;

private final int WINDOW_WIDTH = 200;

private final int WINDOW_HEIGHT = 125;

public ColorWindow()

{

setTitle("Colors");

setSize(WINDOW_WIDTH, WINDOW_HEIGHT);

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

messageLabel = new JLabel("Click a button to " +

"select a color.");

redButton = new JButton("Red");

blueButton = new JButton("Blue");

yellowButton = new JButton("Yellow");

redButton.addActionListener(new RedButtonListener());

blueButton.addActionListener(new BlueButtonListener());

yellowButton.addActionListener(new YellowButtonListener());

panel = new JPanel();

panel.add(messageLabel);

panel.add(redButton);

panel.add(blueButton);

panel.add(yellowButton);

add(panel);

setVisible(true);

}

private class RedButtonListener implements ActionListener

{

public void actionPerformed(ActionEvent e)

{

panel.setBackground(Color.RED);

messageLabel.setForeground(Color.BLUE);

}

}

private class BlueButtonListener implements ActionListener

{

public void actionPerformed(ActionEvent e)

{

panel.setBackground(Color.BLUE);

messageLabel.setForeground(Color.YELLOW);

}

}

private class YellowButtonListener implements ActionListener

{

public void actionPerformed(ActionEvent e)

{

panel.setBackground(Color.YELLOW);

messageLabel.setForeground(Color.BLACK);

}

}

public static void main(String[] args)

{

new ColorWindow();

}

}