static variables and serialization

[Rajeev Trikha]

My source is Sun Certification Sample

I know serialization is not in the exam anymore but I want to understand whether the reported answer is right.

   import java.io.*;
  class Network {
   public static void main(String[] args) throws Exception {
     Traveler t = new Traveler();
     t.x1 = 7; t.x2 = 7; t.x3 = 7;
    // serialize t then deserialize t
     FileOutputStream fo = new FileOutputStream("raj.ser");
     ObjectOutputStream o = new ObjectOutputStream(fo);
     o.writeObject(t);

    FileInputStream fi = new FileInputStream("raj.ser");
     ObjectInputStream oi = new ObjectInputStream(fi);
     Traveler t2 = (Traveler) oi.readObject();
     System.out.println(t2.x1 + " " + t2.x2 + " " + t2.x3);
   }
 }
 class Traveler implements Serializable {
   static int x1 = 0;
   volatile int x2 = 0;
   transient int x3 = 0;
 } 

The reported answer is 0 7 0 but my understanding is that it should be 7 7 0 as the value of the static variable is going to remain unaffected by serialization/unserialization as it is not part of serialized object. Is it an error in the question or is there a way of interpreting the question so the given answer makes sense? Incidentally, I have included the serialization/deserialization code as the original just stated:

4) Given:
2. import java.io.*;
3. public class Network {
4. public static void main(String[] args) {
5. Traveler t = new Traveler();
6. t.x1 = 7; t.x2 = 7; t.x3 = 7;
7. // serialize t then deserialize t
8. System.out.println(t.x1 + " " + t.x2 + " " + t.x3);
9. }
10. }
11. class Traveler implements Serializable {
12. static int x1 = 0;
13. volatile int x2 = 0;
14. transient int x3 = 0;
15. }

If, on line 7, t is successfully serialized and then deserialized, what is the result?

[Harpreet Singh janda]

Yes, You are right output will be "7 7 0"

[Kai Witte]

Hello,

I was pretty upset about the low quality of the sample questions and proposed "correct" answers - which aren't even free. The proposed answer and explanation from your example can only be created of by a total lack of understanding how a simple program runs in general, combined the laziness to not test it.

Maybe the serialization questions in the real exam were all wrong, too, and that's why they had to remove them?

Kai

[T Vergilio]

I'm not impressed either... well, at least it's been corrected here