// MAIN
public static void main(String[] args) {
    Dialog dialog   = new Dialog();
    Register reg    = new Register();

    reg.readFromFile    ("data.txt");
    reg.writeToFile     ("data.txt");

// EN klass lol
public class Register {
        private ArrayList<CD> reg;

        CD CD;

        public Register(){

        }

        public void readFromFile(String fileName){
            Scanner scan = null;

            try {
                scan = new Scanner(new File(fileName));
            } catch (FileNotFoundException e) {
                System.err.println("Filen kunde inte öppnas.");
                System.exit(1);
            }

            while (scan.hasNextLine()) {
                CD = new CD(scan.nextLine(), scan.nextLine());
                reg.add(CD);
            }

            scan.close();
        }

        public void writeToFile(String fileName){
            PrintWriter printWriter = null;
            try {
                printWriter = new PrintWriter(new File(fileName));
            } catch (FileNotFoundException e) {
                System.err.println("Filen kunde inte öppnas.");
                System.exit(1);
            }

            for (int i = 0; i < reg.size(); i++) {
                printWriter.println(reg.get(i));
            }

            printWriter.println("Test Line");

            printWriter.close();
        }
}

// EN till lolol
public class CD {
    private String artist;
    private String title;

    public CD(String artist, String title) {
        this.artist = artist;
        this.title  = title;
    }

    public String getArtist(){
        return artist;
    }

    public String getTitle(){
        return title;
    }

    public String toString(){
        return artist + "\t" + title;
    }
}