code: void configureFilesReloadable(String path) {
  
          try {
              // Running with reloading:
              Path filesPath = FileSystems.getDefault().getPath(path);
              filesUrl = filesPath.toUri().toURL();
          } catch (IOException e) {
              throw new RuntimeException("Error determining files path/url for: " + path, e);
          }
      }
docs: Configures static file serving from a directory. This will be reloadable,
  so is most useful for development (rather than deployment). This
  typically serves files from the <code>src/main/resources/files/...</code>
  directory of your development project.
  <p>
  NB This provides an efficient development workflow, allowing you to see
  static file changes without having to rebuild.