NullPointerException

sarranoob

Hello,

I recently started following some Java tutorials. (Game Programming series on youtube by TheChernoProject)
I'm now at episode 5 and it's the first time we need to run our code (in debug mode).
I have exactly the same code as the tutor, but i get a Null Pointer Exception error. Can someone please take a look at the code and explain what the problem is?

the code is:
[code]package com.sarranoob.lucid;

import java.awt.Canvas;
import java.awt.Dimension;
import javax.swing.JFrame;

public class Game extends Canvas implements Runnable {

private static final long serialVersionUID = 1L;

public static int width = 300;
public static int height = width / 16 * 9;
public static int scale = 3;

private Thread thread;
private JFrame frame;
private boolean running = false;

public Game() {
Dimension size = new Dimension(width * scale, height * scale);
setPreferredSize(size);
}

public synchronized void start() {
running = true;
thread = new Thread(this, "Display");
thread.start();
}

public synchronized void stop() {
running = false;
try{
thread.join();
} catch(InterruptedException e) {
e.printStackTrace();
}

}

public void run() {
while (running) {
System.out.println("Testing...");
}
}

public static void main(String[] args) {
Game game = new Game();
game.frame.setResizable(false);
game.frame.setTitle("Lucid Alpha Testing");
game.frame.add(game);
game.frame.pack();
game.frame.setLocationRelativeTo(null);
game.frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
game.frame.setVisible(true);
game.start();
}

}
[/code]

and the error:
[color=Red]Exception in thread "main" java.lang.NullPointerException
at com.sarranoob.lucid.Game.main(Game.java:48)[/color]

line 48 (where the error occurred) is:
game.frame.setResizable(false);

Thanks on advance.

jounesya

Hello,

These are the most famous errors we're all facing as Java programmers. I faced the exact same issue, I got my answer from here : e-howtogeek.com/187604/illegalargumentexception-nullpointerexception-parameter?show=187604#q187604