docs: @RequirePOST
      public synchronized void doConfigSubmit( StaplerRequest req, StaplerResponse rsp ) throws IOException, ServletException, FormException {
          BulkChange bc = new BulkChange(this);
          try {
              checkPermission(ADMINISTER);
  
              JSONObject json = req.getSubmittedForm();
  
              systemMessage = Util.nullify(req.getParameter("system_message"));
  
              boolean result = true;
              for (Descriptor<?> d : Functions.getSortedDescriptorsForGlobalConfigUnclassified())
                  result &= configureDescriptor(req,json,d);
              
              save();
              updateComputerList();
              if(result)
                  FormApply.success(req.getContextPath()+'/').generateResponse(req, rsp, null);
              else
                  FormApply.success("configure").generateResponse(req, rsp, null);    // back to config
          } finally {
              bc.commit();
          }
      }