Dragon class with inner speed calculator. This class is used to demonstrate aspects of Java serialization.

Dragon.java

public class Dragon implements Serializable {
 
    private static final long serialVersionUID = 1L;
    private double wingSpan;
    private String name;
    private SpeedCalculator speedCalculator = new SpeedCalculator();
 
    public Dragon(double wingSpan, String name) {
        // Input checks. For example, insuring wing size is greater than zero.
        this.wingSpan = wingSpan;
        this.name = name;
    }
 
    public double getWingSpan() {
        return wingSpan;
    }
 
    public double getSpeed() {
        double speed = speedCalculator.calculate(wingSpan);
        return speed;
    }
 
    public String getName() {
        return name;
    }
}