Fire Furry.

//This is the error:Exception in thread "main" java.lang.NullPointerException	at begin.main(begin.java:82)	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)	at java.lang.reflect.Method.invoke(Method.java:597)	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:90)//code belowimport javax.swing.*;import java.awt.*;import java.util.Random;/** * Created by IntelliJ IDEA. * User: User * Date: 29/06/2007 * Time: 13:25:52 * To change this template use File | Settings | File Templates. */public class begin {    public void particle(int x, int y){    }   public static void main(String[] args){       JFrame frame = new JFrame("Fire Furry");       Graphics g = frame.getGraphics();       int particleAmount = 500;       int startx = 20;       int starty = 20;       Color[] particleColor = new Color[particleAmount];       Color[] particleColorList = {Color.RED, Color.ORANGE, Color.WHITE};       int[] particleX = new int[particleAmount];       int[] particleY = new int[particleAmount];       int[] particleVeloX = new int[particleAmount];       int[] particleVeloY = new int[particleAmount];       //Create Random Generator Spock Styles.       random random = new random();       Thread randomThread = new Thread(random);       randomThread.start();       // Set random amount.       random.maxRandom = 3;       random.delay = 10; //ms before new number is generated.              //Set Particle Starting point.       for(int i = 0;i<particleAmount;i++){         particleX[i] = startx;         particleY[i] = starty;       }       //Set Random Velocity.       for(int i = 0;i<particleAmount;i++){           particleVeloX[i] = random.random - (random.maxRandom / 2);           particleVeloY[i] = random.random - (random.maxRandom / 2);       }       //Set Random Colors.       random.maxRandom = 2;       for(int i = 0;i<particleAmount;i++){         particleColor[i] = particleColorList[random.random];         System.out.println(particleColor[i]);       }       //Set Frame Requirements (Size, Location).       frame.setSize(200,200);       frame.setLocation(30,30);       frame.show();       //Begin main loop.       random.maxRandom = 2;       while(true){                  //Move Particles           for(int i = 0;i<particleAmount;i++){               particleX[i] = particleX[i] + particleVeloX[i];               particleY[i] = particleY[i] + particleVeloY[i];               // If particle off screen. Set new values.               if(particleX[i] > frame.getWidth() || particleY[i] > frame.getHeight() || particleX[i] < 0 || particleY[i] < 0){                   particleX[i] = startx; particleY[i] = starty;                   particleColor[i] = particleColorList[random.random];               }           }           //Draw particles.           for(int i = 0;i<particleAmount;i++){            g.setColor(Color.RED);//particleColor[i]);            g.drawLine(particleX[i],particleY[i],particleX[i],particleY[i]);            frame.paintAll(g);           }       }   }}