LTC Owner is: TAPHORN.com
LTC Originator is: TAPHORN.com


Problem description:

When an Object Array (Object[]) is created which contains several different
Objects like e.g. another Object[], a Long objetc and an object of type Locale,
the serialization of the Object[] into a file seems to work correctly. Once the
serialized Object[] gets deserialized again, the following exception is thrown:

Exception in thread "main" java.io.IOException: Unknown marker on stream: 4
   at java.io.ObjectInputStream.readObject(libgcj.so.7rh)
   at java.io.ObjectInputStream.readArrayElements(libgcj.so.7rh)
   at java.io.ObjectInputStream.readObject(libgcj.so.7rh)
   at java.io.ObjectInputStream.readArrayElements(libgcj.so.7rh)
   at java.io.ObjectInputStream.readObject(libgcj.so.7rh)
   at SerializationTest.main(SerializationTest.java:65)

For (de)serialization we used the ObjectOutputStream and 
ObjectInputStream.


Hardware/Software Environment
uname -a shows:
Linux localhost 2.6.17-1.2157_FC5 #1 Tue Jul 11 22:55:46 EDT 2006 i686 i686 i386
GNU/Linux

  We are running the FC rawhide (last update: Aug,4th) on an i386 Intel machine.

  rpm -qa|grep gcj
   libgcj-4.1.1-14
   libgcj-src-4.1.1-14
   libgcj-devel-4.1.1-14
   java-1.4.2-gcj-compat-devel-1.4.2.0-40jpp_100rh
   java-1.4.2-gcj-compat-1.4.2.0-40jpp_100rh
   java-1.4.2-gcj-compat-javadoc-1.4.2.0-40jpp_100rh
   java-1.4.2-gcj-compat-src-1.4.2.0-40jpp_100rh


Please provide contact information if the submitter is not the primary contact.
  Initially the problem was reported by Michael Bauschert
<Michael.Bauschert[at]de.ibm.com> who is able to give further information on
this problem.


Is this reproducible?
  Yes.
  Save the code added at the bottom of this bugzila into a file named
'SerializationTest.java', and perform the following steps:
    1. gcj -C SerializationTest.java
    2. java -cp . SerializationTest sample
    3. The error should be displayed.

Is the system (not just the application) hung?
  No


Did the system produce an OOPS message on the console?
  No


Is the system sitting in a debugger right now?
  No


Additional information:
Here is a sample code which reproduces the error:
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;

public class SerializationTest {

        public static void main(String[] args) throws Exception {
                if (args.length != 1)
                {
                        System.err.println("Usage: java -cp . SerializationTest
filename");
                        return;
                }

                ObjectOutputStream out = new ObjectOutputStream(new
FileOutputStream(args[0]));


                Object[] fiveElementArray = new Object[5];
                fiveElementArray[0] = new Object[7];
                fiveElementArray[1] = Locale.UK;
                fiveElementArray[4] = new Long(0);

                Object[] in1 = new Object[3];
                in1[0] = fiveElementArray;
                out.writeObject(in1);

                HashSet hashSet = new HashSet();
                hashSet.add("Test1");
                hashSet.add(hashSet);
                out.writeObject(hashSet);

                out.flush();
                out.close();

                ObjectInputStream in = new ObjectInputStream(new
FileInputStream(args[0]));

                Object o1 = in.readObject();
                System.out.println("Object #1 " + o1);

                Object o2 = in.readObject();
                System.out.println("Object #2 " + o2);

        }
}

An additional comment here:
The sample code works properly while using a SUN or IBM JVM.