NullPointer

    @EventHandler
    public void onPlayerClickEvent(PlayerInteractEvent event) {

        Player player = event.getPlayer();
        if (player.getItemInHand() != null) {
            if (player
                    .getItemInHand()
                    .getItemMeta()
                    .getDisplayName() //Line 77??
                    .equalsIgnoreCase(
                            "§4§l|:| §d§lŽaidėjai §2§lĮjungti §4§l|:|")) {
                ItemStack visiboff = new ItemStack(Material.INK_SACK, 1,
                        (short) 8);
                ItemMeta visiboffMeta = (ItemMeta) visiboff.getItemMeta();
                visiboffMeta.setDisplayName("§4§l|:| §d§lŽaidėjai §c§lIšjungti §4§l|:|");
                visiboff.setItemMeta(visiboffMeta);
                player.setItemInHand(visiboff);

                //Do Something
            }

            else if (player
                    .getItemInHand()
                    .getItemMeta()
                    .getDisplayName()
                    .equalsIgnoreCase(
                            "§4§l|:| §d§lŽaidėjai §c§lIšjungti §4§l|:|")) {
                ItemStack visibon = new ItemStack(Material.INK_SACK, 1,
                        (short) 10);
                ItemMeta visibonMeta = (ItemMeta) visibon.getItemMeta();
                visibonMeta
                        .setDisplayName("§4§l|:| §d§lŽaidėjai §2§lĮjungti §4§l|:|");
                visibon.setItemMeta(visibonMeta);
                player.setItemInHand(visibon);

                //Do Something
            }
        }
    }