Entity Wither Constructor Undefined

Code:

package me.John.TextBanners;

import org.bukkit.Location;
import org.bukkit.craftbukkit.v1_16_R1.CraftWorld;
import org.bukkit.craftbukkit.v1_16_R1.entity.CraftPlayer;
import org.bukkit.entity.EntityType;
import org.bukkit.entity.Player;
import org.bukkit.util.Vector;

import net.minecraft.server.v1_16_R1.EntityWither;
import net.minecraft.server.v1_16_R1.PacketPlayOutEntityDestroy;
import net.minecraft.server.v1_16_R1.PacketPlayOutSpawnEntityLiving;
import net.minecraft.server.v1_16_R1.WorldServer;

public class Bar {
    private Player p;
    private String message;
    private EntityWither w;

    public Bar(Player p, String message) {
        this.p = p;
        this.message = message;
        update();
    }
 
    public void update() {
        Vector d = p.getLocation().getDirection();
        Location loc = p.getLocation().add(d.multiply(20));
        removeWither();
        WorldServer world = ((CraftWorld)loc.getWorld()).getHandle();
        w = new EntityWither(EntityType.WITHER, world);
        w.setLocation(loc.getX(), p.getLocation().getY(), loc.getZ(), loc.getPitch(), loc.getYaw());
        ((Player) w).setDisplayName(message);
        w.setInvisible(true);
        PacketPlayOutSpawnEntityLiving packet = new PacketPlayOutSpawnEntityLiving(w);
        ((CraftPlayer)p).getHandle().playerConnection.sendPacket(packet);
    }
 
    private void removeWither() {
        if (w!=null) {
            PacketPlayOutEntityDestroy packet = new PacketPlayOutEntityDestroy(w.getId());
            ((CraftPlayer)p).getHandle().playerConnection.sendPacket(packet);
        }
    }
}

in w=new EntityWither(...); it says the constructor is undefined. I have tried defining it with only "world", but it says it needs an entityType as well, so I tried this and it does not work. Eclipse proposes null for that spot which makes me run into NullPointerException. I am not exactly sure what entityType it wants me to use here, or even if I should make a constructor overriding this one

EDIT

Code:

package me.John.TextBanners;

import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.player.PlayerJoinEvent;

public class PlayerJoin implements Listener {
   
    private Main banner;

    public PlayerJoin(Main banner) {
        this.banner = banner;
    }

    @EventHandler
    public void onPlayerJoin(PlayerJoinEvent e) {
        banner.set(e.getPlayer());
    }
}

Apparently another NullPointerExeption exists here in PlayerJoin, specifically in banner.set(e.getPlayer());