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I created a class Car. It includes a location, a double array size 2. I'm trying to create an array of Cars. Here is what I have:

Car[] cars;
cars = new Car[3];

cars[0].location = new double[]{1,6};
cars[1].location = new double[]{10,30};
cars[2].location = new double[]{20,7};

I get an error where I try to declare the location: NullPointerException. How do I resolve this?

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3  
You haven't initialized the elements in the array. –  Sotirios Delimanolis Feb 2 '14 at 2:07

1 Answer 1

up vote 4 down vote accepted

You need to create reference variables for the objects in the array. Your original code simply initializes a Cars array of size 3, but doesn't put any objects inside.

Car[] cars;
cars = new Cars[3];

for (int i=0; i<3; i+=1) {
    cars[i] = new Car();
}

cars[0].location = new double[]{1,6};
cars[1].location = new double[]{10,30};    
cars[2].location = new double[]{20,7};
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