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");
}
}