private static void checkUnique(Set<FileTypeWithDescriptor> descriptors) {
    ConcurrentHashMap<String, FileTypeWithDescriptor> names = new ConcurrentHashMap<>();
    ConcurrentHashMap<String, FileTypeWithDescriptor> displayNames = new ConcurrentHashMap<>();
    ConcurrentHashMap<String, FileTypeWithDescriptor> descriptions = new ConcurrentHashMap<>();
    for (FileTypeWithDescriptor descriptor : descriptors) {
      checkUnique(descriptor, names, "getName", FileType::getName);
      checkUnique(descriptor, displayNames, "getDisplayName", FileType::getDisplayName);
      checkUnique(descriptor, descriptions, "getDescription", FileType::getDescription);
    }
  }
private static void checkUnique(Set<FileTypeWithDescriptor> descriptors)