求简单的java程序！

import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.BorderLayout;
import java.awt.Dimension;
import javax.swing.JSlider;
import javax.swing.JTextField;
import javax.swing.JLabel;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

public class SliderBarDemo {

private JFrame jFrame = null; // @jve:decl-index=0:visual-constraint="135,73"
private JPanel jContentPane = null;
private JSlider jSlider = null;
private JTextField jValueTextField = null;
private JLabel jMinLabel = null;
private JLabel jMaxLabel = null;

/**
* This method initializes jFrame
*
* @return javax.swing.JFrame
*/
private JFrame getJFrame() {
if (jFrame == null) {
jFrame = new JFrame();
jFrame.setSize(new Dimension(372, 125));
jFrame.setTitle("Slider Bar Demo");
jFrame.setC