ByteArrayDataOutput out = ByteStreams.newDataOutput();
  out.writeUTF("BungeeCord"); out.writeUTF("Argument");

  // If you don't care about the player // Player player =
  // Iterables.getFirst(Bukkit.getOnlinePlayers(), null);
  // Else, specify them
  Player plr =  Bukkit.getPlayerExact("spacegeek224");

  plr.sendPluginMessage(p, "BungeeCord",
  out.toByteArray());

@Override
    public void onEnable() {
        this.getProxy();
        ProxyServer.getInstance().getPluginManager().registerListener(this, new ChannelListener());

        this.getProxy();
        ProxyServer.getInstance().registerChannel("Return");
    }

package net.spacegeek224.metro.util;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;

import net.md_5.bungee.api.ProxyServer;
import net.md_5.bungee.api.chat.BaseComponent;
import net.md_5.bungee.api.chat.ComponentBuilder;
import net.md_5.bungee.api.config.ServerInfo;
import net.md_5.bungee.api.event.PluginMessageEvent;
import net.md_5.bungee.api.plugin.Listener;
import net.md_5.bungee.event.EventHandler;

public class ChannelListener implements Listener {

    @EventHandler
    public void onPluginMessage(PluginMessageEvent e) {
        if (e.getTag().equalsIgnoreCase("BungeeCord")) {
            DataInputStream in = new DataInputStream(new ByteArrayInputStream(e.getData()));
            try {
                String channel = in.readUTF(); // channel we delivered
                if(channel.equals("BungeeCord")){
                   ProxyServer.getInstance().broadcast(new ComponentBuilder(e.getReceiver().toString()).create());

                } else {
                    ProxyServer.getInstance().broadcast(new ComponentBuilder(e.getReceiver().toString()+":"+channel).create());

                }
            } catch (IOException e1) {
                e1.printStackTrace();
            }

        }
    }

    public void sendToBukkit(String channel, String message, ServerInfo server) {
        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        DataOutputStream out = new DataOutputStream(stream);
        try {
            out.writeUTF(channel);
            out.writeUTF(message);
        } catch (IOException e) {
            e.printStackTrace();
        }
        server.sendData("Return", stream.toByteArray());

    }
}