Null Pointer Exception on getGraphics()
bufferedimage, draw, java, nullpointerexception, swing
Solution
You're likely trying to get the Graphics context via `getGraphics()` before the JPanel has been rendered, and thus the method returns null. Don't do this. There are problems with using `getGraphics()` on a component to get the Graphics context, one of which is the problem you're seeing above, and another is that the Graphics context obtained will not persist. There are occasions when this is necessary to do, but usually we do passive drawing via `paintComponent(...)`. Often a Swing Timer can be used for the animation loop.
Problem
my application looks like that, i am getting a null pointer exception at the draw() method, to be exact at g.drawImage(img, 0, 0, null) ``` package com.ochs.game; import java.awt.Dimension; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.image.BufferedImage; import javax.swing.JFrame; import javax.swing.JPanel; public class Game extends JPanel implements Runnable{ private static final long serialVersionUID = 8229934361462702491L; public static final int WIDTH = 320; public static final int HEIGHT = 240; public static final int SCALE = 2; public boolean isRunning; private BufferedImage img; private Graphics2D g2d; public Game() { setFocusable(true); requestFocus(); start(); } public void start() { isRunning = true; new Thread(this).start(); } public void stop() { isRunning = false; } public void run() { long start; init(); while(isRunning) { start = System.currentTimeMillis(); update(); render(); draw(); try { Thread.sleep(5 - (System.currentTimeMillis() - start)); } catch (Exception e) { } } } public void init() { img = new BufferedImage(WIDTH*SCALE, HEIGHT*SCALE, BufferedImage.TYPE_INT_RGB); g2d = (Graphics2D) img.getGraphics(); } public void update() { } public void render() { } public void draw() { Graphics g = getGraphics(); g.drawImage(img, 0, 0, null); // <<<<< getting null pointer here! } public static void main(String[] args) { Dimension size = new Dimension(WIDTH*SCALE, HEIGHT*SCALE); Game gameComponent = new Game(); JFrame frame = new JFrame(); frame.setVisible(true); frame.setSize(size); frame.setLocationRelativeTo(null); frame.setResizable(false); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.add(gameComponent); } } ``` Now my question is: why do i get a null pointer exception when trying to draw the bufferedimage called img? I also tried just outputting some string by using drawString() but this just gives myself a nullpointerexception, too. does anyone has an advice?