Hi friend,

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

public class RomanExample extends JFrame {

JTextField tf1 = new JTextField(6);
JTextField tf2 = new JTextField(8);
public static void main(String[] args) {

RomanExample win = new RomanExample();
}

public RomanExample() {
JButton convertButton = new JButton("Convert");
ActionListener doIt = new ActionListener() {

public void actionPerformed(ActionEvent e) {
try {
int val = Integer.parseInt(tf1.getText());
String roman = Roman.int2roman(val);
tf2.setText("" + roman);
}
catch (NumberFormatException ex) {
tf2.setText("Error");
}
}};
convertButton.addActionListener(doIt);
tf1.addActionListener(doIt);
JPanel content = new JPanel();
content.setLayout(new FlowLayout());
content.add(tf1);
content.add(convertButton);
content.add(tf2);
this.setContentPane(content);
this.setTitle("Decimal to Roman");
this.setSize(400,200);
this.setLocationRelativeTo(null);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setVisible(true);
}
}

-------------------------
public class Roman {

final static romvalue[] ROMAN_VALUE_TABLE = {
new romvalue(1000, "M"),
new romvalue(900, "CM"),
new romvalue(500, "D"),
new romvalue(400, "CD"),
new romvalue(100, "C"),
new romvalue(90, "XC"),
new romvalue(50, "L"),
new romvalue(40, "XL"),
new romvalue(10, "X"),
new romvalue(9, "IX"),
new romvalue(5, "V"),
new romvalue(4, "IV"),
new romvalue(1, "I")
};

public static String int2roman(int n) {
if (n >= 4000 || n < 1) {
throw new NumberFormatException("Numbers must be in range 1-3999");
}
StringBuffer result = new StringBuffer(10);
for (romvalue equiv : ROMAN_VALUE_TABLE) {
while (n >= equiv.val) {
n -= equiv.val;
result.append(equiv.romVal);
}
}
return result.toString();
}

private static class romvalue {

int val;
String romVal;
romvalue(int dec, String rom) {
this.val = dec;
this.romVal = rom;
}
}
}
---------------------------------

Read for more information,

http://www.roseindia.net/java/

Thanks,