About serialization

[C Law]

I'm not sure I understand how the state of an object is preserved.

For one thing:

Animal a = new Animal();
try{
FileOutputStream fo = new FileOutputStream("test.ser");
ObjectOutputStream oo = new ObjectOutputStream(fo);
oo.writeObject(a);
oo.close();
}
catch(IOException ex){
ex.printStackTrace();
}

What is test.ser? Is it an actual file? How can I found it?

Secondly, it seems that I can modify instance variable after
the object containing it has been serialized:

public class Animal{
String name = "Mutsang";

public static void main(String[] argv){
Animal a = new Animal();
try{
FileOutputStream fo = new FileOutputStream("test.ser");
ObjectOutputStream oo = new ObjectOutputStream(fo);
oo.writeObject(a);
oo.close();
}
catch(IOException ex){
ex.printStackTrace();
}

a.name = "Tiger";

try{
FileInputStream fi = new FileInputStream("test.ser");
ObjectInputStream oo = new ObjectInputStream(fi);
oo.readObject();
System.out.println(a.name);
oo.close();
}
catch(IOException ex){
ex.printStackTrace();
}
//output is Tiger.

If the state is really saved in "test.ser", how come that when
the object is restored, its "name" field is changed?

Thanks in advance!

[Henry Wong]

Hint: When you run this command...

oo.readObject();

What do you think happens to the object that is returned?

Henry