Sample

1.Screen shot :

Start.
When you click on JCheckBox. The text on JLabel is changed.
When you click on JButton. The text on JLabel is changed.
When you click on JRadioButton, the text changes again.

Here is part of the code. You can implement interface or extend class after the class declaration.

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;

public class ButtonTest extends JFrame 
{ 
    // your codes

    public ButtonTest() {
        // your codes
       
       
       
    }

   // your codes
   
   
    
    
   public static void main(String[] args) {
        JFrame f = new ButtonTest();
	f.setSize(200,100);
	f.setVisible(true);
	f.setDefaultCloseOperation(EXIT_ON_CLOSE);
    }
    
}

2.
A yellow circle with diameter 20 shows up for a single click.
A green square with side length 20 shows up for a double click.

Here is part of the code. You can implement interface or extend class after the class declaration.

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;

public class ClickTest extends JFrame  
{
    // your codes
    
    
    
    
    public ClickTest() {
       // your codes
    
    
    }
    
    public void paint(Graphics g) {
       // your codes
    
    
    
    
    
    }
    
    // your other codes
    
    
    
    
    public static void main(String[] args) {
        JFrame f = new ClickTest();
	f.setSize(200,200);
	f.setVisible(true);
	f.setDefaultCloseOperation(EXIT_ON_CLOSE);
    }
}

3.
What is the output of the following program?

import java.util.*;

public class VectorTest {
    
    public static void main(String[] args) {
        Vector v = new Vector();
	v.add("Java");
	v.add(new Integer(10));
	System.out.println(v);
	v.add(new Double(5.2));
	v.add(1, "PIC");
	System.out.println(v);
	v.set(2, new Integer(7));
	System.out.println(v);
	System.out.println(v.indexOf("Java"));
    }
}

4.
Write a method Vector bigger(Vector v, int num) returns a Vector consists of Integer bigger than num.
Notice that not all the elements in Vector v are Integer.
Hint: Use obj instanceof Integer. The statment returns true if obj is an instance of Integer.

5.
Write a class extends JFrame. It has a number on it to represent the number of seconds remaining. The number decreases by 1 every second till it reaches 0.

At the beginning.
After 11 seconds

The font I use is new Font("Westminster", Font.BOLD, 50).
Here is part of the code. You can implement interface or extend class after the class declaration.

import java.awt.*;
import javax.swing.*;

public class CountdownClock extends JFrame 
{
    private JLabel timeLabel = new JLabel();
    private int initialTime;
       
    public CountdownClock(int initialTime) {
	this.initialTime = initialTime;
	timeLabel.setBackground(Color.white);
	timeLabel.setForeground(Color.green.darker());
        // other codes	
	
	
    }
	
    // other coddes
       
       
    
    
    public static void main(String[] args) {
        CountdownClock clock = new CountdownClock(1000);
	clock.pack();
	clock.setVisible(true);
	clock.setDefaultCloseOperation(EXIT_ON_CLOSE);
	// start the thread 
	// add codes
	
	
    }
}

6. Write a class, extends JFrame.

After 28 seconds, almost half of the circle is blue.
After 45 seconds, 3 quarters of the circle is blue.
After one min and 5 seconds. Small portion of the circle is blue.
The process goes forever.

Here is part of the code. You can implement interface or extend class after the class declaration.

import java.awt.*;
import javax.swing.*;

public class Clock extends JFrame implements Runnable {
    private int time = 0; // from 1 to 60
    // your codes
    
    
    
    
    
    
     
    public static void main(String[] args) {
        Clock clock = new Clock();
	clock.setSize(200,200);
	clock.setVisible(true);
	clock.setResizable(false);
	clock.setDefaultCloseOperation(EXIT_ON_CLOSE);
	// your codes
    }

}