阅读下列程序，请写出该程序的功能。

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

class MyScrollBar extends JScrollBar {

public MyScrollBar(int init, int len, int low, int high){

super(JScrollBar.HORIZONTAL, init, len, low, high);

}

public Dimension getPreferredSize(){

return new Dimension(125, 20);

}

}

class MyWindow extends JFrame implements AdjustmentListener{

private JTextField text;

MyWindow(String s){

super(s);

MyScrollBar tempBar = new MyScrollBar(l0, 10, 0, 255);

Container con = this.getContentPane();

con.setLayout(new GridLayout(2,1));

this.setSize(250, 100);

this.setLocation(100, 100);

tempBar.addA djustmentListener(this);

text= new JTextField("移动滚动条的滑块",20);

con.add(text); con.add(tempBar);

this.setVisible(true);

this.pack();

}

public void adjustmentValueChanged(AdjustmentEvent e){

MyScrollBar myBar=(MyScrO11Bar)e.getAdjustable()；

text.setText("选择的值是："+myBar.getValue())；

}

}public class Test35 {

public static void main(String[] args) {

new MyWindow("滚动条示意程序");

}

}