import java.sql.*;
class test1{
 public static void main(String args[]){
   try{
Class.forName("oracle.jdbc.driver.OracleDriver");
Connection con=DriverManager.getConnection(
"jdbc:oracle:thin:@host:1521:hr","hr","a123");
 Statement stmt=con.createStatement();
ResultSet rs=stmt.executeQuery("select * from emp");
while(rs.next())
 System.out.println(rs.getInt(1)+"  "+rs.getString(2)+"       "+rs.getString(3));
 con.close();
  }catch(Exception e){ System.out.println(e);}
 }
 }

java.lang.ClassNotFoundException: oracle.jdbc.driver.OracleDriver