Sample Code 1

// @Author: Jordan Fisher
// @Version: 2.0

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

public class TemperatureConverter extends JFrame {
	JTextField celcius = new JTextField("", 15);
	JTextField farenheight = new JTextField("", 15);
	JLabel celciusL = new JLabel("C");
	JLabel farenheightL = new JLabel("F");
	JLabel label = new JLabel("Temperature converter");
	JPanel p1 = new JPanel();
	JPanel p2 = new JPanel();

	double c, f;
	String getString;

	public TemperatureConverter() {
		p1.setLayout(new FlowLayout());
		p2.setLayout(new FlowLayout());

		p1.add(celciusL);
		p1.add(celcius);

		p2.add(farenheightL);
		p2.add(farenheight);

		getContentPane().add(label, BorderLayout.NORTH);
		getContentPane().add(p1, BorderLayout.CENTER);
		getContentPane().add(p2, BorderLayout.SOUTH);

		label.setHorizontalAlignment(JLabel.CENTER);

		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setTitle("Temperature Converter");



		celcius.addKeyListener(new KeyAdapter() {
			public void keyReleased(KeyEvent e) {
				System.out.println("Released");
				getString = celcius.getText();
				c = Double.parseDouble(getString);
				System.out.println("Celcius    : " + c);
				f = ((c / 5) * 9) + 32;
				DecimalFormat dp = new DecimalFormat("##.##");
				getString = dp.format(f);
				farenheight.setText(getString);
				System.out.println("Farenheight: " + f);
			}
		});
		farenheight.addKeyListener(new KeyAdapter() {
			public void keyReleased(KeyEvent e) {
				System.out.println("Released");
				getString = farenheight.getText();
				f = Double.parseDouble(getString);
				System.out.println("Farenheight: " + f);
				c = ((f - 32) / 9) * 5;
				DecimalFormat dp = new DecimalFormat("##.##");
				getString = dp.format(c);
				celcius.setText(getString);
				System.out.println("Celcius    : " + c);
			}
		});
	}
	public static void main(String[] args) {
		TemperatureConverter frame = new TemperatureConverter();
		frame.setLocation(100, 100);
		frame.pack();

		frame.setVisible(true);
	}
}