public static boolean isArchive(FileName fileName) {
    String extension = fileName.getExtension();
    return archivesSuffixes.contains(extension.toLowerCase());
  }
Returns whether a folder contains a given file

@param folder A folder
@param file   A file
@return whether a folder contains a given file
olv-vfs/src/main/java/pl/otros/vfs/browser/util/VFSUtils.java