Помогите Failed to remap class

Здравствуйте
Столкнулся я с такой проблемой:
Я разработал свой первый плагин, в компиляции ошибок не было, plugin.yml составлен правильно.
Но при загрузке плагина получаю ошибку:

Код:

2018-07-25 18:21:54 [SEVERE] Could not load 'plugins/dragoncraft.jar' in folder 'plugins' 
org.bukkit.plugin.InvalidPluginException: java.lang.ClassNotFoundException: Failed to remap class plugin.plugin     at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:176)     at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:307)    
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:231)    
at org.bukkit.craftbukkit.v1_5_R3.CraftServer.loadPlugins(CraftServer.java:265)    
 at org.bukkit.craftbukkit.v1_5_R3.CraftServer.<init>(CraftServer.java:243)    
at net.minecraft.server.management.ServerConfigurationManager.<init>(ServerConfigurationManager.java:128)    
at net.minecraft.server.dedicated.DedicatedPlayerList.<init>(SourceFile:11)    
at net.minecraft.server.dedicated.DedicatedServer.func_71197_b(DedicatedServer.java:158)    
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:579)    
at net.minecraft.server.ThreadMinecraftServer.run(SourceFile:573) Caused by: java.lang.ClassNotFoundException: Failed to remap class plugin.plugin    
at org.bukkit.plugin.java.PluginClassLoader.remappedFindClass(PluginClassLoader.java:442)    
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:356)    
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:332)    
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)    
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)    
at java.lang.Class.forName0(Native Method)    
at java.lang.Class.forName(Class.java:348)    
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:165)    
... 9 more 
Caused by: java.lang.IllegalArgumentException    
at org.objectweb.asm.ClassReader.<init>(Unknown Source)     at org.objectweb.asm.ClassReader.<init>(Unknown Source)     at org.objectweb.asm.ClassReader.<init>(Unknown Source)    
at net.md_5.specialsource.RemapperPreprocessor.preprocess(RemapperPreprocessor.java:83)    
at org.bukkit.plugin.java.PluginClassLoader.remappedFindClass(PluginClassLoader.java:398)    
... 16 more

Как исправить эту ошибку?
Сорцы плагина:

Спойлер: plugin.java

Код:

package plugin;

import java.util.logging.Logger;
import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.Location;
import org.bukkit.World;
import org.bukkit.block.Block;
import org.bukkit.command.Command;
import org.bukkit.command.CommandExecutor;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.player.PlayerJoinEvent;
import org.bukkit.event.player.PlayerMoveEvent;
import org.bukkit.plugin.java.JavaPlugin;

public class plugin extends JavaPlugin implements Listener, CommandExecutor{
Logger console = getLogger();
public void OnEnable() {
    console.info("Plugin successfully enabled!");
}
@EventHandler
public void onPlayerJoin(PlayerJoinEvent e)
{
    if(e.getPlayer().hasPermission("dragoncraft.join.message.hide"))
        return;
    String name = e.getPlayer().getName();
    for(Player p:Bukkit.getServer().getOnlinePlayers())
        if(!p.getName().equals(name))
            p.sendMessage("Игрок "+name+" вошёл на сервер!");
}
public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
if(command.getName().equalsIgnoreCase("vk")){
Player player = (Player)sender;
if(player.hasPermission("dragoncraft.command.vk")) {
player.sendMessage(ChatColor.GREEN + "Наша группа ВКонтакте: " + ChatColor.BLUE + "vk.com/game_dc");
return true;
} else {
    player.sendMessage(ChatColor.RED + "Недостаточно прав!");
}
}
if(command.getName().equalsIgnoreCase("explokill")) {
    float explosionPower = 4F;
    Player player = (Player)sender;
    if(player.hasPermission("dragoncraft.troll.explokill")) {
    Player target = player.getServer().getPlayerExact(args[0]);
    target.getWorld().createExplosion(target.getLocation(), explosionPower);
    target.setHealth(0);
    player.sendMessage(ChatColor.DARK_PURPLE + "[DragonCraft Troll] " + ChatColor.AQUA + "Вы взорвали игрока " + ChatColor.RED + target.getName());
    String killer = player.getPlayer().getName();
    String etarget = target.getName();
    console.info("Игрок " + killer + "взорвал игрока" + etarget);
    return true;
    } else {
        player.sendMessage(ChatColor.DARK_RED + "Недостаточно прав!");
    }
}
return false;
}
}

Спойлер: plugin.yml

Код:

name: DragonCraft
author: DragOn4ik
version: 1.0
main: plugin.plugin
commands:
   vk:
      description: VK Group
      permission: dragoncraft.command.vk
      usage: /vk
   explokill:
      description: Explode Player
      permission: dragoncrat.troll.explokill
      usage: /explokill [player]

За говнокод простите, первый раз плагин пишу