@EventHandler
    public void onClick(InventoryClickEvent event){

        if(event.getInventory() == null) return;
        if(event.getClickedInventory() == null) return;
        if(event.getInventory().getName().equals("§ccomme tu veux")){
            Player player = (Player) event.getWhoClicked();
            Material material = event.getCurrentItem().getType();
            event.setCancelled(true);

            if(material == Material.BARRIER){
                player.closeInventory();
            }

            switch (material) {
            case BLAZE_ROD:
                for(Player players : Bukkit.getOnlinePlayers()){
                    player.hidePlayer(players);
                }
                break;
            case BLAZE_POWDER:
                for(Player players : Bukkit.getOnlinePlayers()){
                    player.showPlayer(players);
                }
                break;

            default:

                break;
            }
        }