public final class DebugPlugin extends JavaPlugin {

    private Logger logger;
    private BukkitTask task;

    @Override
    public void onEnable() {
        super.onEnable();
        this.logger = getLogger();

        this.task = Bukkit.getScheduler().runTaskTimerAsynchronously(this, () -> {
            for (Player player : getServer().getOnlinePlayers()) {
                //Bukkit.broadcastMessage("start");
                final ItemStack itemStack = player.getItemInHand();
                if (itemStack.getType() == Material.BOOK) {
                    //Bukkit.broadcastMessage("is book");
                    final ItemMeta itemMeta = itemStack.getItemMeta();
                    if (itemMeta.hasEnchants()) {
                        //Bukkit.broadcastMessage("hasEnchants");
                        final Map<Enchantment, Integer> enchants = itemMeta.getEnchants();
                        String message = enchants.keySet().stream()
                                .map(enchant -> enchant.getName() + " ")
                                .collect(Collectors.joining());
                        //Bukkit.broadcastMessage("sending...");
                        player.spigot().sendMessage(ChatMessageType.ACTION_BAR, new ComponentBuilder(message).create());
                    }
                }
            }
        }, 200L, 60L);

        logger.info("isEnable!");
    }

    @Override
    public void onDisable() {
        super.onDisable();
        if (this.task != null && this.task.getTaskId() != -1) {
            this.task.cancel();
        }
        logger.info("isDisable!");
    }

}