Jdbc connectivity by type 4 driver

I have done a code with database connectivity with driver 4,it copiles,but while running it is showing java.lang.ClassNotFound exception..the code is following...

import java.sql.*;
class JdbcDemo1
{
static Connection con=null;
public static void main(String args[])
{
try
{
Class.forName("oracle.jdbc.driver.OracleDriver");
con=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521","system","123");
System.out.println("connection established");
Thread.sleep(1000);
Statement stmt=con.createStatement();
String createTable="create table test(name varchar2(20),fname varchar2(20))";
   stmt.executeUpdate(createTable);
System.out.println("Table created successfully");
   Thread.sleep(1000);

   String insertQuery="insert into test values('raja','papa')";
   stmt.executeUpdate(insertQuery);
System.out.println("Records inserted successfully");
Thread.sleep(2000);
System.out.println("Plz,wait....data is fetching...");
Thread.sleep(2000);
ResultSet rs=stmt.executeQuery("select * from test");
while(rs.next())
{
System.out.println("name = "+ rs.getString(1) + "fname = "+ rs.getString(2) );
}
}
catch (Exception e1) 
{ 
e1.printStackTrace(); 
} 
finally 
{ 
        try 
          { 
         con.close(); 
          } 
       catch (Exception e1) 
          {         
e1.printStackTrace();
          }
}
}
}.....end of code

please help me out as soon as possible...i m waiting...and i m using oracle 11g as database.