[1.16.5] Spawn Mob Command doesent work

Ingame it says "An iternal error occurred while attempting to perform this command"

heres the error

cmd (open) cmd (close)

Code:

[01:21:05 ERROR]: Error occurred while enabling Projectlostintime v1.0 (Is it up to date?)
java.lang.IllegalArgumentException: Plugin already initialized!
        at org.bukkit.plugin.java.PluginClassLoader.initialize(PluginClassLoader.java:183) ~[spigot.jar:git-Spigot-dcd1643-e60fc34]
        at org.bukkit.plugin.java.JavaPlugin.<init>(JavaPlugin.java:60) ~[spigot.jar:git-Spigot-dcd1643-e60fc34]
        at de.skyflamme.projectlostintime.Projectlostintime.<init>(Projectlostintime.java:21) ~[?:?]
        at de.skyflamme.projectlostintime.commands.lit.<init>(lit.java:13) ~[?:?]
        at de.skyflamme.projectlostintime.Projectlostintime.onEnable(Projectlostintime.java:29) ~[?:?]
        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:264) ~[spigot.jar:git-Spigot-dcd1643-e60fc34]
        at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:337) [spigot.jar:git-Spigot-dcd1643-e60fc34]
        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:403) [spigot.jar:git-Spigot-dcd1643-e60fc34]
        at org.bukkit.craftbukkit.v1_12_R1.CraftServer.enablePlugin(CraftServer.java:381) [spigot.jar:git-Spigot-dcd1643-e60fc34]
        at org.bukkit.craftbukkit.v1_12_R1.CraftServer.enablePlugins(CraftServer.java:330) [spigot.jar:git-Spigot-dcd1643-e60fc34]
        at net.minecraft.server.v1_12_R1.MinecraftServer.t(MinecraftServer.java:422) [spigot.jar:git-Spigot-dcd1643-e60fc34]
        at net.minecraft.server.v1_12_R1.MinecraftServer.l(MinecraftServer.java:383) [spigot.jar:git-Spigot-dcd1643-e60fc34]
        at net.minecraft.server.v1_12_R1.MinecraftServer.a(MinecraftServer.java:338) [spigot.jar:git-Spigot-dcd1643-e60fc34]
        at net.minecraft.server.v1_12_R1.DedicatedServer.init(DedicatedServer.java:272) [spigot.jar:git-Spigot-dcd1643-e60fc34]
        at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:545) [spigot.jar:git-Spigot-dcd1643-e60fc34]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_291]
Caused by: java.lang.IllegalStateException: Initial initialization
        at org.bukkit.plugin.java.PluginClassLoader.initialize(PluginClassLoader.java:186) ~[spigot.jar:git-Spigot-dcd1643-e60fc34]
        at org.bukkit.plugin.java.JavaPlugin.<init>(JavaPlugin.java:60) ~[spigot.jar:git-Spigot-dcd1643-e60fc34]
        at de.skyflamme.projectlostintime.Projectlostintime.<init>(Projectlostintime.java:21) ~[?:?]
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:1.8.0_291]
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) ~[?:1.8.0_291]
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[?:1.8.0_291]
        at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[?:1.8.0_291]
        at java.lang.Class.newInstance(Unknown Source) ~[?:1.8.0_291]
        at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:90) ~[spigot.jar:git-Spigot-dcd1643-e60fc34]
        at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:129) ~[spigot.jar:git-Spigot-dcd1643-e60fc34]
        at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:327) ~[spigot.jar:git-Spigot-dcd1643-e60fc34]
        at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:248) ~[spigot.jar:git-Spigot-dcd1643-e60fc34]
        at org.bukkit.craftbukkit.v1_12_R1.CraftServer.loadPlugins(CraftServer.java:305) ~[spigot.jar:git-Spigot-dcd1643-e60fc34]
        at net.minecraft.server.v1_12_R1.DedicatedServer.init(DedicatedServer.java:205) ~[spigot.jar:git-Spigot-dcd1643-e60fc34]
        ... 2 more

heres the command executor

command executor (open) command executor (close)

Code:

Main main = new Main();

    @Override
    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
        if (label.equalsIgnoreCase("mydebug")) {
            if (sender instanceof Player) {
                Player p = (Player) sender;
                if (args.length > 0) {
                    if (args[0].equalsIgnoreCase("help")) {
                        p.sendMessage(ChatColor.YELLOW + "Help for lit:");
                        p.sendMessage(ChatColor.YELLOW + "witherknight: spawns wither knight");
                    } else {
                        if (args[0].equalsIgnoreCase("witherknight")) {
                            main.spawnWitherKnight(p.getWorld().getName(), p.getLocation().getX(), p.getLocation().getY(), p.getLocation().getZ(),
                                    p.getLocation().getPitch(), p.getLocation().getYaw());
                        }
                    }
                }
            }
        }
        return false;
    }

heres the method from the main calss:

main class method (open) main class method (close)

Code:

    public WitherSkeleton spawnWitherKnight(String worldname, double x, double y, double z, float pitch, float yaw) {
        World w = Bukkit.getWorld(worldname);
        Location loc = new Location(w, x, y, z, pitch, yaw);
        WitherSkeleton witherknight = (WitherSkeleton) w.spawnEntity(loc.add(0, 1, 1), EntityType.ZOMBIE);

        ItemStack dagger = new ItemStack(Material.DIAMOND_SWORD);
        ItemMeta dagger_meta = dagger.getItemMeta();
        dagger_meta.setCustomModelData(1);
        dagger_meta.setDisplayName(ChatColor.RESET + "Diamantkurzschwert");
        dagger_meta.addItemFlags(ItemFlag.HIDE_ATTRIBUTES);
        AttributeModifier daggerAttackDamage = new AttributeModifier(UUID.randomUUID(), "generic.attackDamage", 5.0, AttributeModifier.Operation.ADD_NUMBER);
        dagger_meta.addAttributeModifier(Attribute.GENERIC_ATTACK_DAMAGE, daggerAttackDamage);
        AttributeModifier daggerAttackSpeed = new AttributeModifier(UUID.randomUUID(), "generic.attackSpeed", -1.8, AttributeModifier.Operation.ADD_NUMBER);
        dagger_meta.addAttributeModifier(Attribute.GENERIC_ATTACK_SPEED, daggerAttackSpeed);
        AttributeModifier daggerMovementSpeed = new AttributeModifier(UUID.randomUUID(), "generic.movementSpeed", 0.05, AttributeModifier.Operation.ADD_NUMBER);
        dagger_meta.addAttributeModifier(Attribute.GENERIC_MOVEMENT_SPEED, daggerMovementSpeed);
        dagger_meta.setLore(Arrays.asList(" ",ChatColor.GRAY + "When in Main Hand:",ChatColor.DARK_GREEN + " 6 Attack Damage", ChatColor.DARK_GREEN + " 2.2 Attack Speed"));
        dagger.setItemMeta(dagger_meta);

        witherknight.getEquipment().setItemInMainHand(dagger);

        ItemStack leatherhelmet = new ItemStack(Material.LEATHER_CHESTPLATE);
        LeatherArmorMeta leatherhelmetmeta = (LeatherArmorMeta) leatherhelmet.getItemMeta();
        leatherhelmetmeta.setColor(Color.BLACK);
        leatherhelmet.setItemMeta(leatherhelmetmeta);

        ItemStack leathertunic = new ItemStack(Material.LEATHER_CHESTPLATE);
        LeatherArmorMeta leathertunicmeta = (LeatherArmorMeta) leathertunic.getItemMeta();
        leathertunicmeta.setColor(Color.BLACK);
        leathertunic.setItemMeta(leathertunicmeta);

        ItemStack leatherleggings = new ItemStack(Material.LEATHER_CHESTPLATE);
        LeatherArmorMeta leatherleggingsmeta = (LeatherArmorMeta) leatherleggings.getItemMeta();
        leathertunicmeta.setColor(Color.BLACK);
        leatherleggings.setItemMeta(leatherleggingsmeta);

        ItemStack leatherboots = new ItemStack(Material.LEATHER_CHESTPLATE);
        LeatherArmorMeta leatherbootsmeta = (LeatherArmorMeta) leatherboots.getItemMeta();
        leatherbootsmeta.setColor(Color.BLACK);
        leatherboots.setItemMeta(leatherbootsmeta);

        witherknight.getEquipment().setHelmet(leatherhelmet);
        witherknight.getEquipment().setChestplate(leathertunic);
        witherknight.getEquipment().setLeggings(leatherleggings);
        witherknight.getEquipment().setBoots(leatherboots);


        return witherknight;
    }

 

Code:

Main main = new Main();

You cannot make a new instance of your plugin... Your error literally says that the plugin is already initialized.