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    List<Email> ReadMails(String path) throws IOException {
        File folder = new File(path);
        File[] listOfFiles = folder.listFiles();

        List<Email> mails = new ArrayList<>();

        for (int i = 0; i < listOfFiles.length; i++) {
            if (listOfFiles[i].isFile()) {
                if (listOfFiles[i].getName().endsWith(".json")) {
                    Gson gson = new Gson();
                    // create a reader
                    String data = new String(Files.readAllBytes(Paths.get(listOfFiles[i].getAbsolutePath())));
                    Email mail = gson.fromJson(data, Email.class);
                    mails.add(mail);
                }
            }
        }
        return mails;
    }