Java Database Connectivity (JDBC)

import java.sql.*;
import java.util.*;

class AccountWithdrawl
{

public static void main(String[]args) throws Exception
{

Scanner s = new Scanner(System.in);
System.out.println("Enter the EMPNO :");
int EMPNO = s.nextInt();
System.out.println("Enter the Withdrawl Amount: Rs.");
float amount = s.nextFloat();
Class.forName("oracle.jdbc.driver.OracleDriver");

Connection con = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:server","scott","tiger");
Statement st = con.createStatement();
int count = st.executeUpdate("UPDATE ACCOUNT SET BALANCE = BALANCE - " + amount + " WHERE EMPNO = " +EMPNO);
if(count!=0)
System.out.println(count + "Account updated Successfully");
}
}


The compilation of above program is successful,but when i run it i am getting the following errors

Exception in thread "main" java.lang.ClassNotFoundException: oracle.jdbc.driver.
OracleDriver
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at AccountWithdrawl.main(AccountWithdrawl.java:15)

My oracle version is 11g Release 1..I set my system path as...C:\app\Sandy\product\11.1.0\db_1\jdbc\lib\ojdbc5.jar,even i tried with ojdbc6.jar..still it is showing the above stated error and even i set the path for classes12.jar...."C:\app\Sandy\product\11.1.0\db_1\oui\jlib\classes12.jar"..even that did not work out..

Thanks in advance for the person who solves my problem