double[][] arr = new double[20][4];
Arrays.stream(arr).forEach(a -> Arrays.fill(a, 0));

int rows = 5, column = 7;
int[][] arr = new int[rows][column]; //2D arrays are row major, so always row first
for (int row = 0; row < arr.length; row++)
{	for (int col = 0; col < arr[row].length; col++) {	arr[row][col] = 5; //Whatever value you want to set them to }
}

//this way u can fill your array row by row
Scanner input = new Scanner(System.in);
for (int i = 0; i < row; i++){	for (int j = 0; j < column; j++){ array[i][j] = input.nextInt();	}
}
//this way u can fill your array column by column
//Scanner input = new Scanner(System.in);
for (int i = 0; i < column; i++){	for (int j = 0; j < row; j++){ array[i][j] = input.nextInt();	}
}

IntStream.range(0, array.length).forEach(x -> Arrays.setAll( array[x], y -> String.format("%c%c", letter(x), letter(y))));

static String[][] testArraySetAll() { String[][] array = new String[3][3]; Arrays.setAll(array, x -> { Arrays.setAll(array[x], y -> String.format("%c%c", letter(x), letter(y))); return array[x]; }); return array;
}