code: @Override
      public void doGet(HttpServletRequest request, HttpServletResponse response)
              throws IOException, ServletException {
  
          String api = request.getParameter("api");
  
          if (api == null || api.length() == 0) {
              response.setContentType("text/html; charset=UTF-8");
              getIndex(response.getWriter());
          } else {
              response.setContentType("text/xml; charset=UTF-8");
              getWSDL(api.toUpperCase(), request.getRequestURL()
                              .toString(), response.getWriter());
          }
  
          response.flushBuffer();
      }
docs: Respond to an HTTP GET request. The single parameter, "api", indicates
  which WSDL file to provide. If no parameters are given, a simple HTML
  index is given instead.