code: @SuppressWarnings("rawtypes")
      protected Form getForm(HttpServerExchange exchange) throws IOException {
          final Form form = Application.getInstance(Form.class);
          if (RequestUtils.isPostPutPatch(exchange)) {
              final Builder builder = FormParserFactory.builder();
              builder.setDefaultCharset(StandardCharsets.UTF_8.name());
              try (final FormDataParser formDataParser = builder.build().createParser(exchange)) {
                  if (formDataParser != null) {
                      exchange.startBlocking();
                      final FormData formData = formDataParser.parseBlocking();
                      for (String data : formData) {
                          Deque<FormValue> deque = formData.get(data);
                          if (deque != null) {
                              FormValue formValue = deque.element();
                              if (formValue != null) {
                                  if (formValue.isFileItem() && formValue.getFileItem().getFile() != null) {
                                      form.addFile(Files.newInputStream(formValue.getFileItem().getFile()));
                                  } else {
                                      if (data.contains("[]")) {
                                          String key = StringUtils.replace(data, "[]", "");
                                          for (Iterator iterator = deque.iterator(); iterator.hasNext();)  {
                                              form.addValueList(new HttpString(key).toString(), ((FormValue) iterator.next()).getValue());
                                          }
                                      } else {
                                          form.addValue(new HttpString(data).toString(), formValue.getValue());
                                      }
                                  }    
                              }
                          }
                      }
                  }
              }
              
              form.setSubmitted(true);
          }
  
          return form;
      }
docs: Retrieves the form parameter from a request
  
  @param exchange The Undertow HttpServerExchange
  
  @throws IOException