Need help with Incrementing and Decrementing.Get error "Example.java:8: error: cannot find symbol"

public static void main(String[] args) {
    // Your amazing code goes here...
  System.out.println("We are making a new Pez Dispenser.");
  PezDispenser dispenser = new PezDispenser("Yoda");
  System.out.printf("The dispenser character is %s\n",
                    dispenser.getCharacterName());
  if (dispenser.isEmpty())  {
    System.out.println("It is currently empty");
  }
  System.out.println("Loading...");
  dispenser.load();
  if (!dispenser.isEmpty())  {
    System.out.println("It is no longer empty");
  }
  while (dispenser.dispense())  {
    System.out.println("Chomp!");
}
  if (dispenser.isEmpty())  {
    System.out.println("Ate all the PEZ!");
  }
}