Serialize its create method throws NullPointerException

Hi,

does some one has a clou how to use org.postgresql.util.Serialize to create
a table from my class....


package kermitserver.PL;

import java.io.*;
import java.util.*;
import java.sql.*;
import org.postgresql.util.Serialize;


public class Jk implements Serializable {

	public int oid;

	public Jk() {
	}

	public static void main(String[] args) {
		Jk jk1 = new Jk();
		jk1.oid = 0;   // just in case, only for this test
		
	try {
		Class.forName("org.postgresql.Driver");
		Connection db =
DriverManager.getConnection("jdbc:postgresql:kermitserver", "huub",
"secret");

	
org.postgresql.util.Serialize.create((org.postgresql.Connection)db, jk1);

		db.close();

	} catch (ClassNotFoundException cnfe) {
		cnfe.printStackTrace();
	} catch (SQLException sq) {
		sq.printStackTrace();
	} catch (NullPointerException npe) {
		npe.printStatckTrace();
	}
}


Try to run it and it gave an NullPointerException:

	java.lang.NullPointerException
	at org.postgresql.jdbc2.ResultSet.getString(ResultSet.java:171))
	at org.postgresql.util.Serialize.create(Serialize.java:241)
	at org.postgresql.util.Serialize.create(Serialize.java:220)
	at kermitserver.PL.jk.main(jk.java:37)

I am wondering what the ResultSet is doing. 
I am using jdk1.3.1_01 from Sun, jdbc7.1-1.2.jar on postgresql 7.1.3 on SuSe
7.3

Would be nice if someone has an idea....

greeting Huub