title: How would a senior Software Engineering do this (File Handling)?
body: <p>I have a university assignment, it's mainly focused on file handling in Java.
  The features are simple, you enter a book information like ISBN, Title, Author, ..etc.
  And you can either add it to the database (a txt file in this case), or delete if it is already added, update of select to display the remaining info about the book.</p>
  <p>My approach was that I first read the file in case there is stored data and store them in an ArrayList, so then every action the user affects only the ArrayList until the program is closed.</p>
  <p>My thought process was that this will result to better performance since I don't write to the file on each action.
  is this claim true?
  And was this the better approach over the &quot;store on each action&quot; one?</p>