Date serialization

Question

Hi
I have found interesing (??) problem with Date object serialization. Date object serialized on Sun JVM can't be correctly deserialized on IBM JVM !!
Try run this example on Sun JVM.
import java.io.*;
import java.util.Date;
public class Write {
     public static void main(String[] args) throws IOException {
          Date date = new Date(45,8,1);
          System.out.println("JVM Vendor ["+System.getProperty("java.vm.vendor")+"] Version ["+System.getProperty("java.vm.version")+"]");
          System.out.println("Date ["+date+"], Date time ["+date.getTime()+"]");
          System.out.println("Date timeZoneOffset:"+date.getTimezoneOffset());
          //Serialize date
          ByteArrayOutputStream bout = new ByteArrayOutputStream();
          ObjectOutputStream ous = new ObjectOutputStream(bout);
          ous.writeObject(date);
          ous.flush();
          //write to file
          File outFile = new File("date.bin");
          FileOutputStream fous = new FileOutputStream(outFile);
          fous.write(bout.toByteArray());
          fous.close();
}Result should be:
JVM Vendor [Sun Microsystems Inc.] Version [1.4.2_05-b04]
Date [Sat Sep 01 00:00:00 CEST 1945], Date time [-767930400000]
Date timeZoneOffset:-120
And serialized date object should be written into date.bin file.
Next run this code on IBM JVM:
import java.io.*;
import java.util.Date;
public class Read {
     public static void main(String[] args) throws Exception {
          File inFile = new File("date.bin");
          FileInputStream fis = new FileInputStream(inFile);
          ObjectInputStream ois;
          ois = new ObjectInputStream(fis);
          Date date = (Date) ois.readObject();
          ois.close();
          fis.close();
          System.out.println("JVM Vendor ["+System.getProperty("java.vm.vendor")+"] Version ["+System.getProperty("java.vm.version")+"]");
          System.out.println("Date ["+date+"], Date time ["+date.getTime()+"]");
          System.out.println("Date timeZoneOffset:"+date.getTimezoneOffset());
}On my IBM JVM result is:
JVM Vendor [IBM Corporation] Version [1.4.1]
Date [Fri Aug 31 23:00:00 CET 1945], Date time [-767930400000]
Date timeZoneOffset:-60
Why deserialized date object has different value then before serialization??
Magic date is 1945-09-16, if I set date after - everytjing is ok, if I set date before - something is wrong.

Answer 1

Hi
I have found interesing (??) problem with Date object
serialization. Date object serialized on Sun JVM
can't be correctly deserialized on IBM JVM !!So what, serialization was not meant to be portable accross JVM implementations.