serialization

[adam Lui]

import java.io.*;
 class CodeWalkSeven{
 public static void main(String [] args) {
 Car c = new Car("Nissan", 1500, "blue");
 System.out.println("before: " + c.make + " " +c.weight);
 try {
 FileOutputStream fs = new FileOutputStream("Car.ser");
 ObjectOutputStream os = new ObjectOutputStream(fs);
 os.writeObject(c);
 os.close();
 }catch (Exception e) { e.printStackTrace(); }
 try {
 FileInputStream fis = new FileInputStream("Car.ser");
 ObjectInputStream ois = new ObjectInputStream(fis);
 c = (Car) ois.readObject();
 ois.close();
 }catch (Exception e) { e.printStackTrace(); }
 System.out.println("after: " + c.make + " "
 + c.weight);
 }
 }
 class NonLiving {}
 class Vehicle extends NonLiving { //----class Vehicle
 String make = "Lexus";
 String color = "Brown";
 }
 class Car extends Vehicle implements Serializable {
 protected int weight = 1000;
 Car(String n, int w, String c) {
color = c;
 make = n;
 weight = w;
 }
}

the output is: before: "Nissan 1500 after: Lexus 1500"

according to the source, it is not "Nissan 1500 after: Nissan 1500", because when the object of Car is retrieved, the constructor of Vehicle is excuted and the make variable is reset to Lexus although it was stored as Nissan.

But where is the constrcutor in class Vehicle???

ok if the class is implicitly added the constructor by the compiler, how would the constructor bring effect on the value of make?

[sathi jogi]

hi adam,

It is creating new parent object, when you create any new object, instance variables will be assigned to its default values or initialized values.