Thread: NullPointerException help with array

Hi i'm new to Java, when running the following test class on deb1 i get a NullPointerException. Can someone explain how to fix my array?

Deb1:

public class Deb1 
{
    private int[] array; // create integer array
 
    public int[] allocate() 
    {
	array[0] = 0;
	array[1] = 1;
	array[2] = 2;
	return array;
    }
 
    /**
     * Gets a value from the array of integers.
     */
    public int get(int index) 
    {
	return array[index];
    }
 
    /**
     * Sets a value in the array of integers; returns true if succesful,
     * false otherwise.
     */
    public boolean set(int index, int value) 
    {
	if (index < array.length && index >= 0) {
	    array[index] = value;
	    return true;
	}
	else {
	    return false;
	}
    }
}

TestDeb1:

public class TestDeb1 {
    public static void main(String[] args) {
	Deb1 testObject;
	testObject = new Deb1();
	testObject.allocate();
	if (testObject.get(1) != 1) {
	    System.out.println("Error in get");
	}
	if (!testObject.set(2, 3)) {
	    System.out.println("Error in set");
	}
	if (testObject.get(2) != 2) {
	    System.out.println("Error in set 2");
	}
    }
}

Exception in thread "main" java.lang.NullPointerException
at Deb1.allocate(Deb1.java:20)
at TestDeb1.main(TestDeb1.java:12)

This may not be accurate as i removed some of the comments when posting the code. Just asked a friend on fb and he said i haven't instantiated it.

Fixed the original error by adding = new int[20] to the end of private int[] array. This solved the error because i hadn't created the array itself or set a value for the size,