Nao Descubro onde esta o erro

package com.example.web;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;

public class BeerSelect extends HttpServlet {

       public void doPost(HttpServletRequest request,
                          HttpServletResponse response)
                          throws IOException, ServletException {

 
       response.setContentType("text/html");
       PrintWriter out = response.getWriter();
                   out.println("Beer Selection Advice<br>");
       String c = request.getParameter("color");
             

       BeerExpert be = new BeerExpert();
       List result = be.getBrands(c);
       Iterator it = result.iterator();
       While(it.hasNext()) {
       out.print("<br>try: " + it.next());
       } 
 }
}