JAVA Add Random value in 2 d array(Array Index out of Bounds Exception)

Question

I have a 2D array. I assign it likt this int populations[][] = new int [300][1];. I would like to assign 1 random value (from 0 - 4) into the each row of 300. This what I got so far.

 private void test(){

    for (int i = 0; i < 300; i++){

        for(int j = 0; j < 1; j++){

            populations[i][j] = random.nextInt(4);

       }
    }

    System.out.println(populations.length);
    System.out.println(Arrays.deepToString(populations));
}

However, I got an Array Index out of Bounds Exception of 300. How could I fix that?

http://stackoverflow.com/questions/5554734/what-causes-a-java-lang-arrayindexoutofboundsexception-and-how-do-i-prevent-it — Reimeus, Dec 15 '16 at 17:02
What is the benefit of an 2D array of dimensions of 300x1 vs a 1D array of dimension 300? — Compass, Dec 15 '16 at 17:04
Not a duplicate of that - that OPs issue was using >= which isn't the case here. It may be helpful if you shared more code as nothing seems wrong with this OP — Steven Waterman, Dec 15 '16 at 17:09
I am so dumb ..... I should test more before asking question here..... I assigned a wrong value in the for loop ... — kings077712, Dec 15 '16 at 17:12

score 1 · Accepted Answer · answered Dec 15 '16 at 17:04

Are you sure? This program runs without error...

import java.util.Arrays;
import java.util.Random;

public class Rnd {

    public static void main(String[] args) {
        Random random = new Random();
        int[][] populations = new int[300][1];

        for(int i = 0; i < 300; i++) {
            for(int j = 0; j < 1; j++) {
                populations[i][j] = random.nextInt(4);
            }
        }

        System.out.println(Arrays.toString(populations));
    }
}

JAVA Add Random value in 2 d array(Array Index out of Bounds Exception)

1 Answers1