PremiumKick - Code

package me.MrJonton01.PremiumKick;

import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Random;

import org.bukkit.Bukkit;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.player.PlayerLoginEvent;
import org.bukkit.plugin.java.JavaPlugin;

import net.md_5.bungee.api.ChatColor;

public class Main extends JavaPlugin {

    private String prefix;

    public void onEnable(){
        Bukkit.getMessenger().registerOutgoingPluginChannel(this, "BungeeCord");
        check("prefix", "&7[&3PremiumKick&7]");
        check("lobby-server", "lobby");
        check("kick-msg", "&cDu wurdest von einem &6Premium-Spieler &cgekickt!");
        check("fail-msg", "&cDu konntest nicht zur Lobby gesendet werden!");
        check("no-permission-msg", "&cDieser Server ist voll! Du benötigst &6Premium &cum auf den Server zu connecten!");
        prefix = ChatColor.translateAlternateColorCodes('&', getConfig().getString("prefix"));
    }

    private void check(String path, Object value){
        if(!getConfig().contains(path)){
            getConfig().set(path, value);
            saveConfig();
        }
    }

    @EventHandler
    public void onPlayerJoin(PlayerLoginEvent e){
        Player pj = e.getPlayer();

        if(pj.hasPermission("premium.kick"))
                if(Bukkit.getMaxPlayers() == Bukkit.getOnlinePlayers().size()) {
                    a();
                }
                else {
                    return;
                }
        else{
            pj.sendMessage(ChatColor.translateAlternateColorCodes('&', getConfig().getString("no-permission-msg")));
        }
    }

    public Player getRandomPlayer(){
        String ignorePermission = "premium.kick";
        // get all the online players
        Collection<? extends Player> players = Bukkit.getOnlinePlayers();

        // make a new list, add all of the players who don't have your exempt permission to it
        List<Player> newList = new ArrayList<>();
        for (Player player : players){
            if (!player.hasPermission(ignorePermission)){
                newList.add(player);
            }
        }

        // check if the new list actually has contents, there could be no players online or all the online players could have the exempt permission
        if (newList.size() > 0){

            // since we're getting from the list, you need to subtract 1 from your list size, because array contents start counting at 0
            int size = newList.size() - 1;

            // get a random number
            int random = new Random().nextInt(size);

            // take an object from the list and return it
            return newList.get(random);
        }

        // if the new list has a size of 0, it will return null

        return null;
    }

    public void a(){
        Player player = getRandomPlayer();

        // make sure to check for null as we set it to return null if the list was 0
        if (player != null){
            player.sendMessage(ChatColor.translateAlternateColorCodes('&', getConfig().getString("kick-msg")));
            toServer(player);
        }
    }

    private void toServer(Player p) {
        String targetServer = getConfig().getString("lobby-server");
        if (targetServer.equalsIgnoreCase("none") || targetServer.isEmpty()) {
            p.sendMessage(prefix + " " + ChatColor.translateAlternateColorCodes('&', getConfig().getString("fail-msg").replace("%prefix%", prefix)));
            return;
        }
        ByteArrayOutputStream b = new ByteArrayOutputStream();
        DataOutputStream out = new DataOutputStream(b);
        try {
            out.writeUTF("Connect");
            out.writeUTF(targetServer);
            p.sendPluginMessage(this, "BungeeCord", b.toByteArray());
        } catch (Exception e) {
            p.sendMessage(prefix + " " + ChatColor.translateAlternateColorCodes('&', getConfig().getString("fail-msg").replace("%prefix%", prefix)));
            e.printStackTrace();
        }
    }

}