Plugin Help Bukkit.getWorld() returns null after reload?

Hello, my problem is that the Bukkit.getWorld() returns null, when I reload my server. Does anyone have any idea how to fix this?
My plugins' code(it's very silly and simple, it's my first plugin)

Code:

package com.mscmd.mscmd.MineStrikeCommands;

import java.util.Set;

import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.Location;
import org.bukkit.World;
import org.bukkit.WorldCreator;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import org.bukkit.plugin.java.JavaPlugin;

public final class MineStrikeCommands extends JavaPlugin {
    @Override
    public void onEnable() {
        this.saveDefaultConfig();
    }
 
    @Override
    public void onDisable() {
        this.saveConfig();
    }
 
 
    public Location _tempLoc;
    public String _tempWorld;
    public World _tempWorld_World;
    public String _tempLobbyName;
 
    @Override
    public boolean onCommand(CommandSender sender, Command cmd, String commandLabel, String[] args)
    {
        if (cmd.getName().equalsIgnoreCase("ms")) {
            if(args.length == 1 || args.length > 1)
            { 
                if(args[0].equalsIgnoreCase("setal"))
                {
                    if(sender instanceof Player)
                    {
                        if(args.length < 2)
                        {
                            sender.sendMessage(ChatColor.RED + "Musis zadat jmeno lobby!");
                            return true;
                         
                        } else {
                            Player player = (Player) sender;
                         
                            _tempLoc = player.getLocation();
                            _tempWorld = player.getWorld().getName();
                            _tempLobbyName = args[1];
                         
                            double _x = _tempLoc.getX();
                            double _y = _tempLoc.getY();
                            double _z = _tempLoc.getZ();
                            double _yaw = _tempLoc.getYaw();
                            double _pitch = _tempLoc.getPitch();
                         
                            this.getConfig().set("Lobbys.Coordinates." + _tempLobbyName + ".world", _tempWorld);
                            this.getConfig().set("Lobbys.Coordinates." + _tempLobbyName + ".x", _x);
                            this.getConfig().set("Lobbys.Coordinates." + _tempLobbyName + ".y", _y);
                            this.getConfig().set("Lobbys.Coordinates." + _tempLobbyName + ".z", _z);
                            this.getConfig().set("Lobbys.Coordinates." + _tempLobbyName + ".yaw", _yaw);
                            this.getConfig().set("Lobbys.Coordinates." + _tempLobbyName + ".pitch", _pitch);
                            this.saveConfig();
                         
                            sender.sendMessage(ChatColor.YELLOW + "Lobby " + _tempLobbyName + " uspesne vytvoreno!");
                         
                            return true;
                        }
                    } else {
                        sender.sendMessage(ChatColor.RED + "Pro pouziti tohoto prikazu musis byt hrac!");
                        return true;
                    }
                 
                } else if (args[0].equalsIgnoreCase("list")) {
                    Set<String> _lobbys = this.getConfig().getConfigurationSection("Lobbys.Coordinates").getKeys(false);
                    sender.sendMessage(ChatColor.RED + "List vsech lobby: ");
                    for(String s : _lobbys)
                    {
                        sender.sendMessage(ChatColor.GREEN + s);
                    }
                 
                    return true;
                } else if (args[0].equalsIgnoreCase("delal")){
                    if(args.length < 2)
                    {
                        sender.sendMessage(ChatColor.RED + "Musis zadat jmeno lobby!");
                     
                        return true;
                     
                    } else {
                        if(this.getConfig().getConfigurationSection("Lobbys.Coordinates").contains(args[1]))
                        {
                            this.getConfig().getConfigurationSection("Lobbys.Coordinates").set(args[1], null);
                            this.saveConfig();
                         
                            sender.sendMessage(ChatColor.YELLOW + "Lobby " + args[1] + " uspesne smazano!");
                         
                            return true;
                        } else {
                            sender.sendMessage(ChatColor.RED + "Zadne lobby se jmenem " + args[1] + " neexistuje!");
                         
                            return true;
                        }
                    }
                } else if (args[0].equalsIgnoreCase("join")){
                    if(sender instanceof Player)
                    {
                        if(args.length < 2)
                        {
                            sender.sendMessage(ChatColor.RED + "Musis zadat jmeno lobby!");
                         
                            return true;
                        } else {
                            if(this.getConfig().getConfigurationSection("Lobbys.Coordinates").contains(args[1]))
                            {
                                double _x = Double.parseDouble(this.getConfig().getString("Lobbys.Coordinates." + args[1] + ".x"));
                                double _y = Double.parseDouble(this.getConfig().getString("Lobbys.Coordinates." + args[1] + ".y"));
                                double _z = Double.parseDouble(this.getConfig().getString("Lobbys.Coordinates." + args[1] + ".z"));
                                float _yaw = Float.parseFloat(this.getConfig().getString("Lobbys.Coordinates." + args[1] + ".yaw"));
                                float _pitch = Float.parseFloat(this.getConfig().getString("Lobbys.Coordinates." + args[1] + ".pitch"));
                             
                                _tempWorld = this.getConfig().getString("Lobbys.Coordinates." + args[1] + ".world");
                                _tempWorld_World = Bukkit.getWorld(_tempWorld.trim());
                                _tempLoc.setWorld(_tempWorld_World); _tempLoc.setX(_x); _tempLoc.setY(_y); _tempLoc.setZ(_z); _tempLoc.setYaw(_yaw); _tempLoc.setPitch(_pitch);
                             
                                Player player = (Player) sender;
                                player.teleport(_tempLoc);
                             
                                sender.sendMessage(ChatColor.YELLOW + "Byl jsi uspesne teleportovan do lobby " + args[1]);
                                return true;
                             
                            } else {
                                sender.sendMessage(ChatColor.RED + "Zadne lobby se jmenem " + args[1] + " neexistuje!");
                                return true;
                            }
                        }
                    } else if (args[0].equalsIgnoreCase("leave")){
                     
                     
                    } else {
                        sender.sendMessage(ChatColor.RED + "Pro pouziti tohoto prikazu musis byt hrac!");
                        return true;
                    }
                } else {
                    sender.sendMessage(ChatColor.RED + "List vsech prikazu: ");
                    sender.sendMessage(ChatColor.GREEN + "/ms list - Zobrazi vsechna dostupna lobby");
                    sender.sendMessage(ChatColor.GREEN + "/ms setal jmeno_lobby - Nastavi lobby ");
                    return true;
                }
            } else {
                sender.sendMessage(ChatColor.RED + "List vsech prikazu: ");
                sender.sendMessage(ChatColor.GREEN + "/ms list - Zobrazi vsechna dostupna lobby");
                sender.sendMessage(ChatColor.GREEN + "/ms setal jmeno_lobby - Nastavi lobby ");
                return true;
            }
        }
        return true;
    }
}

In the log, there's NullPointerException at line 130, which is:

Code:

player.teleport(_tempLoc);

But before I reload the server/or restart, it works. I am sure it saves the config and i am sure that it reads the config properly. So please help me...

Oh sorry, it's not line 130, but 127...

Code:

_tempLoc.setWorld(_tempWorld_World); _tempLoc.setX(_x); _tempLoc.setY(_y); _tempLoc.setZ(_z); _tempLoc.setYaw(_yaw); _tempLoc.setPitch(_pitch);

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

@R00t9 is it possible that the world is being unloaded when you reload the server? That can cause it to return null.

 

I don't think so, because it's the default overworld... I am in it when I reload the server so there's no chance this world is not loaded.
BTW: I saw that you made some simple, but useful plugins. I am dreaming of that