Boeing.java from the Interfaces example project

Boeing.java

package flying;

import flying.Flying;
import flying.Coordinate;

public class Boeing implements Flying {
	public static int serial = 1;
	public int number;
	public int passengerCount;
	public double fuelAmount;
	public boolean isFlyingRightNow = false; //INTERFACE

	public Boeing(int passengerCount) {
		this.number = serial;
		serial = serial + 1;
		this.passengerCount = passengerCount;
		System.out.println("Flight no. " + number + " fresh out of the factory!");
	}

	void log(String message) {
		System.out.println("BOEING #" + this.number + ": " + message);
	}

	void refuel(){
		this.fuelAmount = 100;
		log("Refueled successfully");
	}

	void birthOnBoard(){
		passengerCount = passengerCount + 1;
		log("A baby is born in-flight!");
	}

	void takeOff(){
		refuel();
		log("Ladies and gentlemen, about to take off");
	}

	public void land(){
		log("Ladies and gentlemen, we've arrived!");
	}

	public void fly(Coordinate c){
		takeOff();
		fuelAmount = fuelAmount - 80;
		log("This is your captain speaking, we've taken off successfully");
		land();
	}
}