What is wrong with my variables....I really need help soon

Question

I need help. I know I need to add in repaint and change methods, but how come, when I put the starting values of my sliders for R: 0 G: 50 B: 0, the square is not green when it loads? IT is just black. What should happen, at least what I think[i] should happen, is that the rectangle would load green. And should the line:
JPanel = new Rectglbe
JPanel = new JPanel
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class Slider extends JFrame {
        int red, blue, green;
        public Slider() {
                super("ColorChanger");
                setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                //Info
                String Run = "Running, Close Program For Prompt\n";
                System.out.println(Run);
                //Labels
                JLabel RedLabel = new JLabel("                                             Red:");
                JLabel GreenLabel = new JLabel("               Green:");
                JLabel BlueLabel = new JLabel("               Blue:");
                //Red Slider
                JSlider pickR = new JSlider(JSlider.VERTICAL, 0, 255, 0);
                pickR.setMajorTickSpacing(50);
                pickR.setMinorTickSpacing(5);
                pickR.setPaintTicks(true);
                pickR.setPaintLabels(true);
                //Green Slider
                JSlider pickG = new JSlider(JSlider.VERTICAL, 0, 255, 50);
                pickG.setMajorTickSpacing(50);
                pickG.setMinorTickSpacing(5);
                pickG.setPaintTicks(true);
                pickG.setPaintLabels(true);
                //Blue Slider
                JSlider pickB = new JSlider(JSlider.VERTICAL, 0, 255, 0);
                pickB.setMajorTickSpacing(50);
                pickB.setMinorTickSpacing(5);
                pickB.setPaintTicks(true);
                pickB.setPaintLabels(true);
                JPanel pane = new Rectgl();
                pane.add(RedLabel);
                pane.add(pickR);
                pane.add(GreenLabel);
                pane.add(pickG);
                pane.add(BlueLabel);
                pane.add(pickB);
                setContentPane(pane);
                public int getValueR(int color){
                        return red;
                public int getValueG(int color){
                        return green;
                public int getValueB(int color){
                        return blue;
                public void paintComponent(Graphics comp) {
                        Graphics2D comp2D = (Graphics2D)comp;
                        comp2D.fillRect(0,0, 100, 210);
                        Color JL = new Color(red,green,blue);
                        comp2D.setColor(JL);
        public static void main(String[] args) {
                Slider frame = new Slider();
                frame.pack();
                frame.setVisible(true);
                frame.show();
  /*      class Rectgl extends JPanel {
                public void paintComponent(Graphics comp) {
                        Graphics2D comp2D = (Graphics2D)comp;
                        comp2D.fillRect(0,0, 100, 210);
                        Color JL = new Color(red,green,blue);
                        comp2D.setColor(JL);

Answer 1

Thank you, sorry forgot that message. Could you please put it here again, extensively commented, explain why you changed position of Rectgl.class, what other methods you added do?
Thanks.