servlet predict

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		try{
			HttpSession session=request.getSession();

			RequestDispatcher rd=null;

			Class.forName("oracle.jdbc.Driver.OracleDriver");
			Connection con=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:xe","hr","Admin");
			String itemid=null;
			itemid=request.getParameter("id");
			Statement st=con.createStatement();
			ResultSet rs=st.executeQuery("select quantity from item where id='"+id+"'");
		    int value;
		    while(rs.next())
			{
		    	value=rs.getInt("quantity");
			if(value<4)
			{	session.setattribute("itemid",id);
				rd.getRequestDisspatcher("FormDisplay.jsp")

			}

		}
	}