public void showAuthors(List<Message> messages, List<Authors> authors) {
    for (Message message : messages) {
        int authorId = message.getAuthorId();
        for (Authors author : authors) {
            if (author.getId() == authorId)
                authorName = author.getFullName();
                break;
        }
        System.out.println("Message id is " + message.getId() +
                           " author is " + authorName);
    }
}