[1.16] Npc WorldServer thing doesent Work

I don't know why but I have a problem with NMS. I want to make an NPC but it doesn't really work with the WorldServer.

The Error is:
"Inconvertible types; cannot cast 'org.bukkit.World' to 'org.bukkit.craftbukkit.v1_16_R3.CraftServer'"


I implemented NMS using BuildTools and here is my code:

Code:

    public static void createNPC(Player player) {
        World w = Bukkit.getWorld("world");
        MinecraftServer server = ((CraftServer) Bukkit.getServer()).getServer();
        WorldServer world = ((CraftServer)w).getHandle();
        GameProfile gameProfile = new GameProfile(UUID.randomUUID(), ChatColor.AQUA + "" + ChatColor.BOLD + "Practice");
    }

Can anyone help me?

 

I watched a youtube how I can create an NPC, is it not good?

 

@Kopflos You probably meant to cast World to CraftWorld, not CraftServer.