1  public class Car extends Vehicle
  2  {
  3     // This instance variable is added to the subclass
  4     private String licensePlateNumber;
  5     
  6     public Car()
  7     {
  8        // Use the public interface to access the instance variable of the superclass
  9        setNumberOfTires(4); // same as this.setNumberOfTires(4)
 10        licensePlateNumber = "??????";
 11     }
 12  
 13     // This method is added to the subclass
 14     public void setLicensePlateNumber(String newValue)
 15     {
 16        licensePlateNumber = newValue;
 17     }
 18  
 19     // This method overrides a method from the superclass
 20     public String getDescription() 
 21     {
 22        return "A car with license plate " + licensePlateNumber;
 23     }
 24  
 25     // This class inherits the getNumberOfTires and setNumberOfTires methods
 26  }