• I would have class for each of automobile, bicycle, motorboat, sailboat, submarine, airplane, hovercraft, balloon, horse-drawncarts. Each of these would derive from base class vehicle.

• I would have an interface for each of motor_powered_vehicle, nature_powered_vehicle, personally_powered_vehicle, animal_powered_vehicle, land_vehicle, air_vehicle, and water_vehicle.

• Using interfaces allows me to group these categories of vehicle, possibly with overlap but still have them belong to their various classes. For example, interface air_vehicle is implemented by airplane, hovercraft, and balloon, which interface water_vehicle might be implemented by motorboat, sailboat, submarine, and hovercraft. Using interfaces also deals with the lack of multiple-inheritance in Java.

• A method that I would want to include in the vehicle class, but not override in any derived classes would be getName(), which gets the name of the vehicle.

• A method that I would want to over-ride would be getSpeedRange(), which gets the speed range of the vehicle.