Thread: Exception in Main NullPointerException?

Hello!
I'm trying to make a program where the ball moves to the right of the screen but my program compiles correctly. It's when I run it is when this pops up:
Exception in thread "main" java.lang.NullPoinerException
at java.awt.Container.addImpl(Unknown Source)
at java.awt.Container.add(Unknown Source)
at javax.swing.JFrame.addImpl(Unknown Source)
at java.awt.Container.add(Unknown Source)
at FirstGame.<init><FirstGame.java:18>
at FirstGame.main<FirstGame.java:27>

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.util.*;
import java.util.concurrent.*;
//Start
class FirstGame extends JFrame
{
	private PaintSurface canvas;
 
	public FirstGame() 
	{
		JFrame frame = new JFrame();
		frame.setSize(800, 600);
		frame.setResizable(false);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.add(canvas,BorderLayout.CENTER);
 
		ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(3);
		executor.scheduleAtFixedRate(new paintSpriteThread(frame), 0L, 20L, TimeUnit.MILLISECONDS);
 
	}
 
	public static void main(String[] args)
	{
		new FirstGame();
	}
}
class paintSpriteThread implements Runnable
{
 
	JFrame c;
 
	public paintSpriteThread(JFrame c)
	{
		this.c = c;
	}
 
	public void run()
	{
		c.repaint();
	}
}
 
class PaintSurface extends JComponent
{
	int x = 400;
 
	int y = 300;
 
	int d = 20;
 
	public void paint(Graphics g)
	{
		Graphics2D g2 = (Graphics2D)g;
		g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);
		Shape ball = new Ellipse2D.Float(x,y,d,d);
 
		x+=1;
 
		g2.setColor(Color.RED);
		g2.fill(ball);
	}
}

Welp, with every error I will learn something new!
Thank you to all who reply with helpfullness!
lil_misfit

Wow, it was that simple thanks!

lil_misfit