code: public static HttpResponse literalHtml(final String text) {
          return new HttpResponse() {
              @Override
              public void generateResponse(StaplerRequest req, StaplerResponse rsp, Object node) throws IOException, ServletException {
                  rsp.setContentType("text/html;charset=UTF-8");
                  PrintWriter pw = rsp.getWriter();
                  pw.print(text);
                  pw.flush();
              }
          };
      }
docs: Serves an HTML response.