title: Methods of storing permanent data in java
body: <p>I am currently doing a programming assignment and it says that we should
  "store all the data in a data file and need to check the compatibility of the user PIN and account no. validity"</p>
  
  <p>Unfortunately my lecturer has not taught us about data files, and when I googled I found two different answers,</p>
  
  <ol>
  <li>Store data in notepad (.txt) file</li>
  <li>Store data in csv file</li>
  </ol>
  
  <p>MY QUESTION IS WHICH ONE IS A DATA FILE? and how do you retrieve the user PIN (after its typed from buffer reader) to check whether both are correct?
  Any Help is GREATLY APPRECIATED!! </p>