1D array to 2d array

public int[][] getInt2DArray(String str) {
    String[] arrStr  = str.split(" ");
    int arrLength = arrStr.length;
    int size = (int) Math.sqrt(arrLength);
    int[][] arrInt = new int[size][size];
    for (int i = 0; i < size; i++) {
        for (int j = 0; j < size; j++) {
            arrInt[i][j] = Integer.parseInt(arrStr[j+i*size]);
        }
    }
    return arrInt;
}