code: @Override
      public void doGet(HttpServletRequest request, HttpServletResponse response)
              throws ServletException {
          try {
              
              // Get parameters
              String foParam = request.getParameter(FO_REQUEST_PARAM);
              String xmlParam = request.getParameter(XML_REQUEST_PARAM);
              String xsltParam = request.getParameter(XSLT_REQUEST_PARAM);
  
              if (foParam != null) {
                  renderFO(foParam, response);
              } else if ((xmlParam != null) && (xsltParam != null)) {
                  // Note: Not current supported but may be added in a future release. DWD
                  //renderXML(xmlParam, xsltParam, response);
              } else {
                  response.setContentType("text/html");
                  PrintWriter out = response.getWriter();
                  out.println("<html><head><title>Error</title></head>\n"
                          + "<body><h1>FOPServlet Error</h1><h3>No 'source' "
                          + "request param given.</body></html>");
              }
          } catch (Exception ex) {
              throw new ServletException(ex);
          }
      }
docs: {@inheritDoc}