关于SliderPanel中的setPaintTicks()疑问!

Question

package src;
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;public class SliderPanel extends JPanel implements ChangeListener{
public SliderPanel(){
setLayout(new BorderLayout());

JSlider slider1=new JSlider(JSlider.VERTICAL,0,100,50);//水平标尺,0到100默认在50位置上.0位于左方.
slider1.addChangeListener(this);
slider1.setMajorTickSpacing(10);
slider1.setMinorTickSpacing(2);
slider1.setPaintTicks(true);  //我设置false也没见视图有什么变化?试问怎在代码中起着什么作用?
add(slider1,BorderLayout.EAST);

JSlider slider2=new JSlider(JSlider.VERTICAL,0,100,50);
slider2.addChangeListener(this);
slider2.setMajorTickSpacing(10); //主刻度尺分度.
slider2.setMinorTickSpacing(2);  //小刻度尺分度.
slider2.setPaintTicks(true);
add(slider2,BorderLayout.WEST);

JSlider slider3=new JSlider(JSlider.HORIZONTAL,0,100,50);//垂直标尺,0到100默认在50位置上.0位于下方.
slider3.addChangeListener(this);
slider3.setMajorTickSpacing(10);
slider3.setMinorTickSpacing(2);
slider3.setPaintTicks(true);
add(slider3,BorderLayout.SOUTH);

JSlider slider4=new JSlider(JSlider.HORIZONTAL,0,100,50);
slider4.addChangeListener(this);
slider4.setMajorTickSpacing(10);
slider4.setMinorTickSpacing(2);
slider4.setPaintTicks(false);
add(slider4,BorderLayout.NORTH);

}
public void stateChanged(ChangeEvent e){
JSlider js=(JSlider)(e.getSource());
System.out.println(js.getValue());

}
public static void main(String[] args) {
JFrame f = new JFrame ("SliderPanel Example");
    JPanel j = new SliderPanel();
    
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);     f.getContentPane().add (j, BorderLayout.CENTER);
    f.setSize (300, 300);
    f.setVisible(true);
}
}