I am getting a null point error when initializing an array grid of objects

I am trying to initialize an array grid of objects and get a null point error when I do so. It should be calling the object Constructor in Cell each iteration of the loop. Instead I am getting the error. Please help.

public class Spread extends JPanel {
private JPanel outputArea;
private JTextArea numberDead;
private JTextArea totalInfected;
private JTextArea newInfections;
private Integer totalDead;
private Integer total;
private Integer newInfected;
private Integer length = 60;
private Integer width = 100;
private Cell[][] label;
public void makeOutputArea() {
int a;
int b;
outputArea = new JPanel(new GridLayout(length, width, -1, -1));
outputArea.setBorder(BorderFactory.createEmptyBorder(2,2,2,2));
for (a = 0; a < (length - 1); a++){
for (b = 0; b < (width - 1); b++)
label[a][b] = new Cell(); //nullpointerror is located here.
label[a][b].setPreferredSize(new Dimension(10, 10));
label[a][b].setOpaque(true);
outputArea.add(label[a][b]);
outputArea.setVisible(true);
if (label[a][b].getInfected() == true) ++total;
}
}
public JPanel getOutputArea() {
return outputArea;
}
...Additional code follows.

This is the Cell class it should be initializing in the array. As you can see it has a constructor, which should be called for each loop. Instead it is giving a null pointer and never initializing each cell object.

import java.awt.Color;
import java.util.Random;
import javax.swing.JLabel;
@SuppressWarnings("serial")
public class Cell extends JLabel{
private int iteration;
private boolean infected;
private boolean dead;
private boolean immune;
private Random generator = new Random(); //Random number Generator
private static int infectionRate = 5;
private static int deathRate = 3;
public void setIteration(int i) {
iteration = i;
}
public int getIteration() {
return iteration;
}
public void setInfected(boolean b) {
infected = b;
}
public boolean getInfected() {
return infected;
}
public void setDead(boolean a) {
dead = a;
}
public boolean getDead() {
return dead;
}
public void setImmune(boolean i) {
immune = i;
}
public boolean getImmune() {
return immune;
}
public Cell() {
setImmune(false);
setDead(false);
setIteration(0);
if (generator.nextInt(100) < infectionRate) {
setInfected(true);
setIteration(++iteration);
}
else setInfected(false);
color();
}
public void color() {
if (getInfected() == true) setBackground(Color.RED);
else if (getDead() == true) setBackground(Color.BLACK);
else setBackground(Color.GREEN);
}
public void updateInfection(boolean b) {
try {
if (getImmune() == true) return;
else if (getDead() == true) return;
else if (getInfected() == true) {
setIteration(++iteration);
if (iteration >=4) {
if (generator.nextInt(100) < deathRate) {
setInfected(false);
setDead(true);
return;
}
else {
setInfected(false);
setImmune(true);
return;
}
}
return;
}
else {
if (generator.nextInt(100) <= 75) {
setInfected(true);
setIteration(++iteration);
return;
}
else return;
}
}
finally {
this.color();
}
}
}

Cell [][] label is a two-dimentional array in java.
So you have to allocate the memory for it first.

Only then you can execute code like:

label[a][b] = new Cell();

This is a lot of information about how to correctly allocate memory to 2-dimensional arrays in java, quick googling reveals this tutorial