java编程 继承关系

class Transport {

public Transport() {
}
}

class Bus extends Transport {

private String busName;

public Bus(String busName) {
this.busName = busName;
}
}

class Train extends Transport {

private String trainName;
private double trainSpeed;

public Train(String trainName, double trainSpeed) {
this.trainName = trainName;
this.trainSpeed = trainSpeed;
}
}

class Airplane extends Transport {

private String airplaneName;
private double airplaneSpeed;
private String Voyage;

public Airplane(String airplaneName, double airplaneSpeed, String Voyage) {
this.airplaneName = airplaneName;
this.airplaneSpeed = airplaneSpeed;
this.Voyage = Voyage;
}
}