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