import java.util.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;
import javax.swing.border.*;

public class CapslockKey extends JPanel implements ActionListener
{
static final String st = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
JButton buttonList[];
String buffer = "";
JTextField text;
JButton capsLock;
boolean capslock;

public void key() {
text = new JTextField(20);
text.setActionCommand(""+ buffer);
add(text);
int n = st.length();
buttonList = new JButton[n];
for (int i = 0; i < n; i++) {
buttonList[i] = new JButton( "" + st.charAt(i) );
add(buttonList[i]);
buttonList[i].addActionListener(this);
}
capsLock = new JButton("CapsLock Key");
add(capsLock);
capsLock.addActionListener(this);
}
public void actionPerformed( ActionEvent e) {
int n = st.length();
if (e.getSource() == capsLock)
{
if (capslock)
capslock = false;
else capslock = true;
}
else{
for (int i = 0; i < n; i++)
{
if (e.getSource() == buttonList[i])
{
if (capslock)
{
buffer += st.charAt(i);
}
else
{
buffer += st.toLowerCase().charAt(i);
}
text.setText(""+ buffer);
break;
}
}
}
}
public CapslockKey(){
JPanel pane = new JPanel();
add(pane);
}
public static void main(String s[])
{
JFrame frame = new JFrame();
CapslockKey keys= new CapslockKey();
frame.getContentPane().add(keys,"Center");
keys.key();
frame.setSize(500,200);
frame.setVisible(true);
}
}

i think u soooo respectable , thank u so much so much so much,.....,thank u to share it. can u give me same idea for ALT , SHIFT and CTRL button ?? and if instead of array {String st = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";} use Stack or ArrayList ?. if we can how ? thank u ...