Describe the Superclass in Inheritance ?

In this example you start through defining a more common MotorVehicle class.
public class MotorVehicle {

private String licensePlate; // e.g. "New York A456 324"
private double speed; // kilometers per hour
private double maxSpeed; // kilometers per hour
private String make; // e.g. "Harley-Davidson", "Ford"
private String model; // e.g. "Fatboy", "Taurus"
private int year; // e.g. 1998, 1999, 2000, 2001, etc.
private int numberPassengers; // e.g. 4

// constructors
public MotorVehicle(String licensePlate, double maxSpeed,
String make, String model, int year, int numberOfPassengers) {
this(licensePlate, 0.0, maxSpeed, make, model, year, numberOfPassengers);
}

public MotorVehicle(String licensePlate, double speed, double maxSpeed,
String make, String model, int year, int numberOfPassengers) {

// I could add some more constraints like the
// number of doors being positive but I won't
// so that this example doesn't get too big.
this.licensePlate = licensePlate;
this.make = make;
this.model = model;
this.year = year;
this.numberPassengers = numberOfPassengers;

if (maxSpeed >= 0.0) {
this.maxSpeed = maxSpeed;
}
else {
maxSpeed = 0.0;
}

if (speed < 0.0) {
speed = 0.0;
}

if (speed <= maxSpeed) {
this.speed = speed;
}
else {
this.speed = maxSpeed;
}

}


// getter (accessor) methods
public String getLicensePlate() {
return this.licensePlate;
}

public String getMake() {
return this.make;
}

public String getModel() {
return this.model;
}

public int getYear() {
return this.year;
}

public int getNumberOfPassengers() {
return this.numberPassengers;
}

public int getNumberOfPassengers() {
return this.numberWheels;
}

public double getMaxSpeed() {
return this.maxSpeed;
}

public double getSpeed() {
return this.speed;
}

// setter method for the license plate property
protected void setLicensePlate(String licensePlate) {
this.licensePlate = licensePlate;
}

// accelerate to maximum speed
// put the pedal to the metal
public void floorIt() {
this.speed = this.maxSpeed;
}

public void accelerate(double deltaV) {

this.speed = this.speed + deltaV;
if (this.speed > this.maxSpeed) {
this.speed = this.maxSpeed;
}
if (this.speed < 0.0) {
this.speed = 0.0;
}
}
}
The MotorVehicle class has all the features shared through motorcycles and cars, but it leaves the number of wheels unspecified, and it doesn't have a numberDoors field since not all motor vehicles have doors. It also forms the fields and the setLicensePlate() method protected on the other hands of private and public.