Exception in thread "main" java.lang.NullPointerException at Draw.<init>(Draw.java:78), at Draw.main(Draw.java:152)

[falcons13atlanta]

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

public class Draw extends Frame implements ActionListener, ItemListener {

// Initial Frame size
static final int WIDTH = 800; // frame width
static final int HEIGHT = 600; // frame height

// Color choices
static final String COLOR_NAMES[] = {"None", "Red", "Blue", "Green"};
static final Color COLORS[] = {null, Color.red, Color.blue, Color.green};

// Button control
Button circle;
Button roundRec;
Button threeDRec;
Button line;
Button square;
Button oval;
Button clear;
Button reset;

// Color choice box
Choice colorChoice;

// the canvas
DrawCanvas canvas;

/**
* Constructor
*/
public Draw() {
super("Java Draw");
setLayout(new BorderLayout());

// create panel for controls
Panel topPanel = new Panel(new GridLayout(3, 1));
add(topPanel, BorderLayout.NORTH);

// create button control
Panel buttonPanel = new Panel(new FlowLayout(FlowLayout.LEFT));
topPanel.add(buttonPanel);

circle = new Button("Circle");
buttonPanel.add(circle);
roundRec = new Button("Rounded Rectangle");
buttonPanel.add(roundRec);
threeDRec = new Button("3D Rectangle");
buttonPanel.add(threeDRec);

Panel buttonPanel1 = new Panel(new FlowLayout(FlowLayout.LEFT));
topPanel.add(buttonPanel1);

line = new Button("Line");
buttonPanel1.add(line);
square = new Button("Square");
buttonPanel1.add(square);
oval = new Button("Oval");
buttonPanel1.add(oval);

// add button listener
circle.addActionListener(this);
roundRec.addActionListener(this);
threeDRec.addActionListener(this);
line.addActionListener(this);
square.addActionListener(this);
oval.addActionListener(this);
clear.addActionListener(this);
reset.addActionListener(this);

// create panel for color choices
Panel colorPanel = new Panel(new FlowLayout(FlowLayout.LEFT));
topPanel.add(colorPanel);
Label label = new Label("Filled Color:");
colorPanel.add(label);
colorChoice = new Choice();
for(int i=0; i<COLOR_NAMES.length; i++) {
colorChoice.add(COLOR_NAMES[i]);
}
colorPanel.add(colorChoice);
colorChoice.addItemListener(this);

// create the canvas
canvas = new DrawCanvas();
add(canvas, BorderLayout.CENTER);

Panel buttonPanel2 = new Panel(new FlowLayout(FlowLayout.LEFT));
topPanel.add(buttonPanel2);

clear = new Button("Clear");
buttonPanel2.add(clear);
reset = new Button("Reset");
buttonPanel2.add(reset);
} // end of constructor


/**
* Implementing ActionListener
*/
public void actionPerformed(ActionEvent event) {
if(event.getSource() == circle) { // circle button
canvas.setShape(DrawCanvas.CIRCLE);
}
else if(event.getSource() == roundRec) { // rounded rectangle button
canvas.setShape(DrawCanvas.ROUNDED_RECTANGLE);
}
else if(event.getSource() == threeDRec) { // 3D rectangle button
canvas.setShape(DrawCanvas.RECTANGLE_3D);
}
else if(event.getSource() == line) { // 3D rectangle button
canvas.setShape(DrawCanvas.LINE);
}
else if(event.getSource() == square) { // 3D rectangle button
canvas.setShape(DrawCanvas.SQUARE);
}
else if(event.getSource() == oval) { // 3D rectangle button
canvas.setShape(DrawCanvas.OVAL);
}
else if(event.getSource() == clear) { // 3D rectangle button
Graphics g = null;
canvas.paint(g);
}
else if(event.getSource() == reset) { // 3D rectangle button
canvas.setShape(DrawCanvas.CIRCLE);
Color color = COLORS[0];
}
}

/**
* Implementing ItemListener
*/
public void itemStateChanged(ItemEvent event) {
Color color = COLORS[colorChoice.getSelectedIndex()];
canvas.setFilledColor(color);
}

/**
* the main method
*/
public static void main(String[] argv) {
// Create a frame
Draw frame = new Draw();
frame.setSize(WIDTH, HEIGHT);
frame.setLocation(150, 100);

// add window closing listener
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent event) {
System.exit(0);
}
});

// Show the frame
frame.setVisible(true);
}
}

[GregBrannon]

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