How do i spawn an item in the player inventory when spawning in world?

EntityConstruct event

Thank you  had to do some changes

 

 

    private static final String NBT_KEY = "drugsnalcoholics.firstjoin";

   

    @SubscribeEvent

    public void onPlayerJoin(PlayerLoggedInEvent event) {

        NBTTagCompound data = event.player.getEntityData();

        NBTTagCompound persistent;

        if (!data.hasKey(EntityPlayer.PERSISTED_NBT_TAG)) {

            data.setTag(EntityPlayer.PERSISTED_NBT_TAG, (persistent = new NBTTagCompound()));

        } else {

            persistent = data.getCompoundTag(EntityPlayer.PERSISTED_NBT_TAG);

        }

 

if (!event.player.capabilities.isCreativeMode) {

        if (!persistent.hasKey(NBT_KEY)) {

            persistent.setBoolean(NBT_KEY, true);

            event.player.inventory.addItemStackToInventory(new ItemStack(ItemManager.Cola));

        }

}

    }