Swing Test to learn Java GUIs - GUI for string reverser https://www.dropbox.com/s/ib6fk9pmhyua2jb/Screenshot%202014-08-18%2012.31.10.png

SwingTest.java

package com.jainlabs;

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

public class SwingTest {
    private JFrame frame;
    private JLabel result;
    private JTextField textfield;
    private JButton button;

    public SwingTest() {
        frame = new JFrame("String Reverser");
        frame.setLayout(new BorderLayout());

        result = new JLabel("Result: ");
        textfield = new JTextField("Enter String Here");

        button = new JButton("Reverse");
        button.addActionListener(new ReverseListener(result, textfield));

        frame.add(textfield, BorderLayout.WEST);
        frame.add(button, BorderLayout.EAST);
        frame.add(result, BorderLayout.SOUTH);

        frame.setSize(200,200);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingTest swingtest = new SwingTest();
    }

}

class ReverseListener implements ActionListener {
    private JLabel label;
    private JTextField textfield;

    public ReverseListener(JLabel label, JTextField textfield) {
        this.label = label;
        this.textfield = textfield;
    }

    public void actionPerformed(ActionEvent e) {
        String s1 = textfield.getText();
        String s2 = "";
        for (int i = s1.length() - 1; i >= 0; i--) {
            s2 += s1.charAt(i);
        }

        label.setText(s2);
    }
}