Why Scanner followed by a bufferedReader gives a Null pointer Exception ?

Question

    int n = scanner.nextInt();
        scanner.nextLine()
        String[] unsorted = new String[n];
        for (int i = 0; i < n; i++) {
            String unsortedItem = br.readLine();
            unsorted[i] = unsortedItem; }

int n =Integer.parseInt(br readLine());
        String[] unsorted = new String[n];
        for (int i = 0; i < n; i++) {
            String unsortedItem = br.readLine();
            unsorted[i] = unsortedItem; }

Just changing the 1st section of code with 2nd section solves the Exception in my Code , why is this happening ??

You can check the code ,by giving input :
Length of Array , followed by its elements
Eg -
4
1
2
3
4
https://code.sololearn.com/c3R2631V6N3f/?ref=app

Answer 1

Never done it, but this might help.
https://stackoverflow.com/q/7635917/10057029

Answer 2

It didn't helped ,but I get to know something new.

Answer 3

LukArToDo or Danijel Ivanović , Can you explain this ?