For java I/O I am reading from a file but when I get the data and try to send it to another method it gives me a null pointer error

Question

I want to take integers from a file and put put them into an array but it keeps giving me a null pointer error. The text file is 100 lines with a single integer on each. When I debug it the file is being read and the proper integer is being stored but when I try to send it to my popBArray method it doesn't work.

public void readBoardFile(String filename) {
    try {
        Scanner filescanner = new Scanner(new File(filename));
        while (filescanner.hasNextLine()) {
            String line = filescanner.nextLine();
            int num = Integer.parseInt(line);
            popBarray(num);
        }
        filescanner.close();
    } catch (IOException e) {
        System.out.println(e);
    } catch (Exception e) {
        System.out.println(e);
    }
}
int c = 0;
public void popBarray(int sent) {
    BoardA[c] = sent;
    c++;
}

Ok but.. can you show us the `popBarray` method ? And it's enough to use only the `Exception` catch, but still, not a good idea (it's better to use specific exceptions rather than the general `Exception`, so I suggest you to remove the second *catch*) — user1234SI., Feb 21 '20 at 22:11
For some reason when I got rid of the exception it started working properly. Idk why but thank you. — Bill, Feb 21 '20 at 22:24

score 0 · Answer 1 · answered Feb 21 '20 at 22:55

You may not initialize BoardA.

The code may help you.

    public void readBoardFile(String filename) {
        try {
            Scanner filescanner = new Scanner(new File(filename));
            while (filescanner.hasNextLine()) {
                String line = filescanner.nextLine();
                int num = Integer.parseInt(line);
                popBarray(num);
            }
            filescanner.close();
        }catch (IOException e){
            System.out.println(e);
        }catch (Exception e){
            System.out.println(e);
        }
    }

    int c = 0;

    public int[] BoardA = new int[100];  // initialize BoardA.

    public void popBarray(int sent) {
        BoardA[c] = sent;
        c++;
    }

For java I/O I am reading from a file but when I get the data and try to send it to another method it gives me a null pointer error

1 Answers1