HTML are not that Dynamic so you must be Creative to make it look Dynamic. YOu can use Javascript or Ajax to do it. But i dont know that yet. So here is my solution using only JSP and Servlet.
In your Servlet you should have this code
wherein OptionFromServlet is a String that you will be passing from Servlet to the JSP
<select Type="ComboBox" name="drop">
<%=OptionFromServlet>
</select>
In your Servlet you have this
String Temp[] = {"One","Two","Three"}; //here is where your list is
String OptionToJSP=null;
Int ctr = Temp.length();
for(int i=0; i<ctr; i++){
OptionToJSP += "<OPTION>" + Temp[i] + "</OPTION>";
} OptionToJSP = OptionToJSP.substring(4);
//Then Return OptionToJSP to the JSP. . .
The only problem with this is when the page is loaded the combox is null. You have to put a refresh, to Load the data from the Servlet to the JSP. =P
I Hope that Helps