String sql="insert into    billingdetail(ID,billingstartdate,billingenddate
,billingamount,customerid) values('"+ID+"','"+billingstartdate+"','"+billingenddate+"','"
+billingamount+"','"+customerid+"')";

Class.forName("com.mysql.jdbc.Driver");
Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/mydbb"
,"root","gm@i‌​l@123");
Statement st=con.createStatement();
String sql=("SELECT id,name,design,statuss,jobfamilyy,jobtitlee,billablee FROM infoo");
String sql1=("SELECT customerid,customername FROM customerdetail");
ResultSet rs = st.executeQuery(sql);

<div style="width:200px; float:left;">
    <select name="customerid" onchange="showCustomer1(this.value)">
       <option VALUE="blank" SELECTED>Please Select
           <% while (rs2.next())
             {%> <option VALUE="<%=rs2.getString(1)%>">
                <%=rs2.getString(1)%> <%}%>
    </select> </div></div>
    <% String customerid=request.getParameter("customerid");
        ResultSet rs5=st.executeQuery("SELECT customername FROM
         customerdetail where customerid="+ customerid +"");
     <% while(rs5.next()) { %>
        <tr><td><%=rs5.getString(1)%></td></tr>
     <%}%>