Array list with integers, receiving an error

Question

I'm running this on an xml file and when I click on that particular button relating to this code it gives me an error. I think it has something to do with the arraylist combined with integers.

    public void doError(ActionEvent actionEvent) {
    ArrayList<Integer> integers =null;

    for (int i = 0; i < 100; i++) {
        integers.add(i);
    }

"when I click on that particular button relating to this code it gives me an error" - cool, thanks for sharing. Was there a question in there somewhere? — rmlan, Dec 12 '16 at 22:24
Use java when you know java. Seems like you need a bit more practicing. — SporreKing, Dec 12 '16 at 22:29
Why else would I be here? I am new to java so obviously some things will get overlooked. I'm here to learn and get better. — bringerofrain, Dec 12 '16 at 22:31

score 2 · Answer 1 · answered Dec 12 '16 at 22:24

2

ArrayList is never instantiated.

public void doError(ActionEvent actionEvent) {
ArrayList<Integer> integers = new ArrayList<Integer>();

for (int i = 0; i < 100; i++) {
    integers.add(i);
}

answered Dec 12 '16 at 22:24

Luminous_Dev

614
6
14

That seemed to fix the issue. Appreciate your help! :) – bringerofrain Dec 12 '16 at 22:28
1

`new ArrayList<>();` you don't need to repeat the type. – David Conrad Dec 12 '16 at 22:52

Abdelhak · Answer 2 · 2016-12-12T22:26:42.870

2

You need to initialize the ArrayList like this:

   ArrayList<Integer> integers = new ArrayList<Integer>();

Because you can't add integer to an ArrayList null

edited Dec 12 '16 at 22:26

answered Dec 12 '16 at 22:25

Abdelhak

8,299
4
22
36

I completely overlooked that. Thanks for your help friend – bringerofrain Dec 12 '16 at 22:29
`new ArrayList<>();` you don't need to repeat the type. – David Conrad Dec 12 '16 at 22:53

Array list with integers, receiving an error

2 Answers2