public class Main extends JavaPlugin{

    @Override
    public void onEnable() {

        Bukkit.getServer().getMessenger().registerOutgoingPluginChannel(this, "ChatMessage");

        this.getCommand("msgme").setExecutor(this);
    }

    @Override
    public void onDisable() {



    }

    @Override
    public boolean onCommand(CommandSender sender, Command cmd, String commandLabel, String[] args){

        if(cmd.getName().equalsIgnoreCase("msgme")){

            if(!(sender instanceof Player)){
                System.out.println("This command does not support console usage");
                return true;
            }

            Player player = (Player) sender;

            if(args.length == 0){
                player.sendMessage("/msgme <player> <message>");
                return true;
            }

            StringBuilder message = new StringBuilder();

            for(int i = 1; i < args.length; i++)
                message.append(args[i]);

            ByteArrayOutputStream stream = new ByteArrayOutputStream();
            DataOutputStream out = new DataOutputStream(stream);

            try {
                out.writeUTF("Message");
                out.writeUTF(args[0]);
                out.writeUTF(message.toString());
            } catch (IOException e) {
                e.printStackTrace();
            }

            player.sendPluginMessage(this, "ChatMessage", stream.toByteArray());

            System.out.println("SENT: " + message);

            return true;
        }
        return false;
    }

}