title: How to change a final variable with a Deep-Copy-Constructor?
body: <p>I have to create a deep copy constructor of a Movie which should have the same serial like the committed Object. 
  The first steps I think are already correct but when I try:
  "this.serial = that.serial" it gives a warning and says I can't override <strong>final</strong> variables.</p>
  
  <p>I could solve this problem when I remove the <strong>final</strong> keyword, but that is not allowed.
  Can anyone help me to change the <strong>final int serial</strong> variable without removing the final keyword?</p>
  
  <pre><code>private int serial;
  private String title;
  private FSK fsk;
  private boolean isRent;
  
  private final int serial;
  private static int nextSerial;
  
  Movie(String title, FSK fsk) {
      this.title = title; 
      this.fsk = fsk;
      this.serial = nextSerial;
      nextSerial++;
  
  }
  Movie(Movie that) {
      this(new String(that.title), that.fsk);
      this.serial = that.serial;
      }
  </code></pre>