Throws Exception when jdbc connect to Oracle

Question

Hi! I'm waiting for your answers.
When i use jdbc to connect Oracle,system throws exceptions as follows:
java.lang.ClassCastException: oracle.sql.converter.CharacterConverter12Byte
oracle.sql.CharacterSet1Byte oracle.sql.CharacterSet1Byte.getInstance (int,racle.sql.converter.CharacterConverter)
          CharacterSet1Byte.java:82
     oracle.sql.CharacterSet oracle.sql.CharacterSetWithConverter.getInstance(int)     CharacterSetWithConverter.java:85
I code in Oracle9i Jdeveloper 9.0.2. The Oracle version is 9.0.2.
My code example is as follows:
package mypackage2;
import java.sql.*;
import oracle.jdbc.driver.*;
public class Class1
public Class1()
public static void main(String[] args)
Class1 class1 = new Class1();
Connection conn = null;
try
DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());
//exception throws in getConnection()
conn = DriverManager.getConnection
("jdbc:oracle:thin:@localhost:1521:CR","system","CR2001");
catch (Exception e)
e.printStackTrace();

Answer 1

import java.io.*;
import java.sql.*;
import java.text.*;
import oracle.jdbc.driver.*;
public class viewtable
     Connection con;
     Statement st;
     public viewtable (String args[]) throws ClassNotFoundException,FileNotFoundException,IOException,SQLException
     url="jdbc:oracle:thin:system/manager@IP:1521:SID";
     Class.forName ("oracle.jdbc.driver.OracleDriver");
     try
     con=DriverManager.getConnection(url);
          st = con.createStatement ();
          doexample ();
          st.close ();
          con.close ();
     }catch(SQLException e)
          System.err.println(e.getMessage());
     public void doexample () throws SQLException
     ResultSet rs = st.executeQuery("select * from sales");
          if(rs!=null) {
          while(rs.next())
               int a = rs.getInt("no");                    System.out.println("NO = "+a);
          rs.close();
     public static void main (String args[])
          System.out.println ("Oracle Exercise 1 \n");
          try
               viewtable test = new viewtable(args);
          } catch (Exception ex)
               System.err.println ("Exception caught.\n"+ex);
               ex.printStackTrace ();
the above is the full code, please check the problem....many thanks