Thread: Can't find class WindowCloser

I am working on my final project for class and I am having problems finding the .class file to run the program. Any help would be greatly appreciated!

import java.awt.*;
import java.awt.event.*;

public class ShepGrisPickColor {
public static void main(String[] args) {
Frame f = new PickColorFrame("Pick Color");
f.setSize(300, 300);
f.setVisible(true);
}
}
class PickColorFrame extends Frame {
private Label redLabel =
new Label("Red = 128", Label.CENTER);
private Label greenLabel =
new Label("Green = 128", Label.CENTER);
private Label blueLabel =
new Label("Blue = 128", Label.CENTER);
private Scrollbar redBar =
new Scrollbar(Scrollbar.HORIZONTAL, 128, 1, 0, 256);
private Scrollbar greenBar =
new Scrollbar(Scrollbar.HORIZONTAL, 128, 1, 0, 256);
private Scrollbar blueBar =
new Scrollbar(Scrollbar.HORIZONTAL, 128, 1, 0, 256);


public PickColorFrame(String title) {

super(title);
setBackground(new Color(128, 128, 128));
setLayout(new GridLayout(6, 1));

ScrollbarListener listener = new ScrollbarListener();


add(redBar);
redBar.addAdjustmentListener(listener);
add(redLabel);


add(greenBar);
greenBar.addAdjustmentListener(listener);
add(greenLabel);


add(blueBar);
blueBar.addAdjustmentListener(listener);
add(blueLabel);


addWindowListener(new WindowCloser());
}

class ScrollbarListener implements AdjustmentListener {
public void adjustmentValueChanged(AdjustmentEvent evt) {
int red = redBar.getValue();
int green = greenBar.getValue();
int blue = blueBar.getValue();

redLabel.setText("Red = " + red);
greenLabel.setText("Green = " + green);
blueLabel.setText("Blue = " + blue);

Color newColor = new Color(red, green, blue);
redLabel.setBackground(newColor);
greenLabel.setBackground(newColor);
blueLabel.setBackground(newColor);
}
}
}


The error I am getting is --
cannot find symbol - class WindowCloser
This line is highlighted --
addWindowListener(new WindowCloser());

Thank you in advance for any help and advise.

I found the problem. Thank you so much for the info!