Error instantiating in Java

In my course on Java OO, I've assembled a class to perform certain functions. But they always return NullPointException. If I do the same thing within the main method, without creating any class, everything works fine.

What am I doing wrong?

Excerpt that gives error using the class I created:

public class Main {

    public static void main(String[] args) throws FileNotFoundException {
    // write your code here

        Movie movie = new Movie();
        movie.setMovieFile("movies.txt");

        System.out.println(movie.getMovieListSize());
    }
}

If I do the same thing inside within Main()

public class Main {

    public static void main(String[] args) throws FileNotFoundException {
    // write your code here

       File file = new File("movies.txt");
       Scanner scanner = new Scanner(file);

       if (scanner.hasNextLine()){
           System.out.println(scanner.nextLine());
       }
    }
}

And this is the class I wrote and every object returns error:

public class Movie {

   private List<String> movies;
   private File file;
   private Scanner scanner;
   private boolean hasSetted;

    public Movie() {
    }

    public void setMovieFile(String movieFile) throws FileNotFoundException {
        file = new File(movieFile);
        scanner = new Scanner(file);

        while (scanner.hasNextLine()){
            movies.add(scanner.nextLine());
        }

        hasSetted = true;
    }

    public String getMovie(int position){
        return movies.get(position);
    }

    public int getMovieListSize(){
        return movies.size();
    }

}

This code is in github tbm: link