Problems with Private

Look at the instance variables in Video:

class Video
{
  private String  title;    // name of the item
  private int     length;   // number of minutes
  private boolean avail;    // is the video in the store?

  . . .

They are declared private, which means that only code that is part of Video can see these variables. Even though they are included by inheritance in the child class Movie, they cannot directly be used in that class. This code does not compile:

class Movie extends Video
{
 . . .
  public String toString()
  {
    return title + ", " + length + " min. available:" + avail +  // these private variables can't be accessed
           " dir: " + director + ", rating:  " + rating ; 
  }
  . . .
}

It tries to use private variables of the parent class.

One way to gain access to private variables is to use getter and setter methods of the parent class (as was done a few pages ago.)