Java Database Connectivity (JDBC)

I'm trying to issue a SELECT ... FROM ... FOR UPDATE, and under specific verified conditions runs an UPDATE (where the current is positioned!).

The error code I get is:
ORA-01002: Fetch out of sequence.

Here you are my code:
/////////////////////START
import java.sql.*;
import oracle.jdbc.*;
import oracle.sql.*;

public class SelForUpdDin{

static{
try{
Class.forName("oracle.jdbc.driver.OracleDriver");
}
catch(Exception e){e.printStackTrace();}
}
// Queries and cursor name
public static void main (java.lang.String[] args){
String cursorName = null;
int codice = 0;
String cognome = null;
String job = null;
int manager = 0;
java.sql.Date dataAss = null;
int salario = 0;
int commissioni = 0;
int reparto = 0;
String rowid = null;
String sqlSelect = "SELECT empno, ename, "+
"job, mgr, hiredate, sal, comm, deptno, ROWID "+
"FROM scott.emp FOR UPDATE";

String sqlUpdate = "UPDATE scott.emp SET comm = ? WHERE ROWID = ? ";
try {
Connection con = DriverManager.getConnection("jdbc:Oracle:oci8:@","system","manager");

// Esecuzione della SELECT e produzione del RESULT SET
Statement stmt = con.createStatement();

ResultSet rs = stmt.executeQuery(sqlSelect);

PreparedStatement ps = con.prepareStatement(sqlUpdate);

while (rs.next()) {
codice = rs.getInt(1);
cognome = rs.getString(2);
job = rs.getString(3);
manager = rs.getInt(4);
dataAss = rs.getDate(5);
salario = rs.getInt(6);
commissioni = rs.getInt(7);
reparto = rs.getInt(8);
rowid = rs.getString(9);
// Applicazione della business logic
if (reparto == 30)
{ System.out.println (cognome + " in dept= "+ reparto +
" with salary=" + salario + " has a commission= " +
commissioni);
int newcomm = 5555;
ps.setInt(1,newcomm);
ps.setString(2,rowid);
ps.executeUpdate();
}
else
{ System.out.println (cognome + " in dept= "+ reparto +
" with salary=" + salario + " has a commission= " + commissioni);
} // if - else

} // end while

rs.close();
ps.close();
stmt.close();
}
catch(Exception e)
{
e.printStackTrace();
}

} // end main()
} // end class




//PS.
//Many thanks to Bachar and Elangovan that ansewerd me to my previous posting and addressed me towards the right solution