Item in second hand while anyone join

Hi, anyone know how can I add an event here, when the players join they gets shields to second hand? Spigot 1.16.4

Code:

public class PlayerJoin implements Listener
{
    @EventHandler
    public void onJoin(final PlayerJoinEvent e) throws Exception {
        final Player p = e.getPlayer();
        JoinMessageAPI.onJoined(p);
        final ItemBuilder boots = new ItemBuilder(Material.DIAMOND_BOOTS).addEnchantment(Enchantment.PROTECTION_ENVIRONMENTAL, 2);
        final ItemBuilder chestplate = new ItemBuilder(Material.DIAMOND_CHESTPLATE).addEnchantment(Enchantment.PROTECTION_ENVIRONMENTAL, 2);
        final ItemBuilder helmet = new ItemBuilder(Material.DIAMOND_HELMET).addEnchantment(Enchantment.PROTECTION_ENVIRONMENTAL, 2);
        final ItemBuilder leggings = new ItemBuilder(Material.DIAMOND_LEGGINGS).addEnchantment(Enchantment.PROTECTION_ENVIRONMENTAL, 2);
        final ItemBuilder sword = new ItemBuilder(Material.DIAMOND_SWORD).addEnchantment(Enchantment.DAMAGE_ALL, 2).addEnchantment(Enchantment.DURABILITY, 2);
        final ItemBuilder goldenapple = new ItemBuilder(Material.GOLDEN_APPLE, 3);
        final ItemBuilder tarcza = new ItemBuilder(Material.SHIELD, 1);
        p.getInventory().clear();
        p.getInventory().setBoots(boots.build());
        p.getInventory().setChestplate(chestplate.build());
        p.getInventory().setHelmet(helmet.build());
        p.getInventory().setLeggings(leggings.build());
        for (final PotionEffect effect : p.getActivePotionEffects()) {
            p.removePotionEffect(effect.getType());
        }
        ChatUtil.giveItems(p, sword.build());
        ChatUtil.giveItems(p, goldenapple.build());
        p.setMaxHealth(20.0);
        p.setHealth(20.0);
    }
}

 

Code:

p.getInventory().setItemInOffHand(ITEMSTACK);

 

tysm!