public String[][] listAlbums() {
        Logger.getLogger(BooksFolderAnalyser.class.getName()).entering(BooksFolderAnalyser.class.getName(), "listAlbums");
        try {
            File[] allfiles = listAlbumsFiles();
            if (allfiles == null) {
                Logger.getLogger(BooksFolderAnalyser.class.getName()).exiting(BooksFolderAnalyser.class.getName(), "listAlbums", null);
                return null;
            }
            Arrays.sort(allfiles);
            final File[] allFilesValue = allfiles;
            final List<String[]> albums = new ArrayList<>();
            for (File allFilesValue1 : allFilesValue) {
                if (allFilesValue1.isDirectory()) {
                    albums.add(new String[]{allFilesValue1.getName(), ""});
                } else {
                    String albumFullName = allFilesValue1.getName();
                    int indexOfExtension = albumFullName.lastIndexOf(".");
                    albums.add(new String [] {albumFullName.substring(0, indexOfExtension), albumFullName.substring(indexOfExtension)});
                }
            }
            Logger.getLogger(BooksFolderAnalyser.class.getName()).exiting(BooksFolderAnalyser.class.getName(), "listAlbums", albums.toArray(new String[0][0]));
            return albums.toArray(new String[0][0]);
        } catch (Exception ex) {
            Logger.getLogger(BooksFolderAnalyser.class.getName()).log(Level.SEVERE, "Unknown exception", ex);
            new InfoInterface(InfoInterface.InfoLevel.ERROR, "unknown");
        }
        Logger.getLogger(BooksFolderAnalyser.class.getName()).exiting(BooksFolderAnalyser.class.getName(), "listAlbums", new String[0][0]);
        return new String[0][0];
    }