code: private List<File> locateModules() {
      File[] files = modRoot.listFiles();
      List<File> modFiles = new ArrayList<>();
      for (File file : files) {
        if (file.isDirectory()) {
          // Check to determine whether the directory is a valid module directory.
          boolean isValid = true;
          try {
            new ModuleIdentifier(file.getName());
          } catch (Exception e) {
            isValid = false;
          }
  
          // If the directory is a valid module name then check for a mod.json file.
          if (isValid) {
            File modJson = new File(file, MOD_JSON_FILE);
            if (modJson.exists()) {
              modFiles.add(file);
            }
          }
        }
      }
      return modFiles;
    }
docs: Locates all modules in the local repository.