Embedded Technologies

Hello everyone.

I develop CDC application for J9 on Pocket PC and have a problem
with serialization of an object containing database connection. I am
using hsqldb CDC version and database enabler for J9.
While serializing I get an exception

java.io.NotSerializableException:
org.hsqldb.jdbc.jdbcConnection

I am confused as I do not use this class excplicite in my project. I am using

org.hsqldb.jdbcDataSource implements javax.sql.DataSource.

More details follow here:
I've got an object of

class DBOntModelImpl extends OntModelImpl implements DBOntModel

The class has a field

transient private Connection dbConnection;

The connection is created as

org.hsqldb.jdbcDataSource dataSource = new jdbcDataSource();
dbConnection = dataSource.getConnection(url);

Knowing that db connection cannot be serialized I did as it is written in the Sun's tutorial at
http://java.sun.com/developer/technicalArticles/Programming/serialization/
namely I set connection as transient, I implemented writeObject and readObject methods and tried to serialize DBOntModelImpl. What I get is:

java.io.NotSerializableException: org.hsqldb.jdbc.jdbcConnection
at
java.io.ObjectOutputStream.checkSerializable(Unknown Source)
at
java.io.ObjectOutputStream.writeNewObject(Unknown Source)
at
java.io.ObjectOutputStream.writeObjectInternal(Unknown Source)
at
java.io.ObjectOutputStream.writeObject(Unknown Source)
at
java.io.ObjectOutputStream.writeObject(Unknown Source)
at
java.io.ObjectOutputStream.writeFieldValues(Unknown Source)
etc.

The code for serializing method is following:

private void writeObject(ObjectOutputStream out) throws IOException
	{
		this.closeDBConnection();
		out.defaultWriteObject();
	}

How should I serialize my model then if this does not work??
I have sources of hsqldb-cdc but have no sources for jdbc. I have search the internet but found no similar problem/solution.

Thanks for any clues and ask for details if you need.