java滚动条调整RGB色的问题

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.AdjustmentEvent;
import java.awt.event.AdjustmentListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollBar;

public class T {

public static void main(String[] args) {
final JFrame f = new JFrame();
final JScrollBar red = new JScrollBar();
final JScrollBar green = new JScrollBar();
final JScrollBar blue = new JScrollBar();
red.setMaximum(255);
red.setMinimum(0);
red.setValue(255);
green.setMaximum(255);
green.setMinimum(0);
green.setValue(200);
blue.setMaximum(255);
blue.setMinimum(0);
blue.setValue(128);

//给滚动条加监听器
AdjustmentListener cl = new AdjustmentListener(){
public void adjustmentValueChanged(AdjustmentEvent e) {
setBG(f,red.getValue(),green.getValue(),blue