bungee.java

	public static CompletableFuture<ByteArrayDataInput> sendPluginMessage(String channel, String... data) {
		return sendPluginMessage(Iterables.getFirst(Bukkit.getOnlinePlayers(), null), channel, data); 
	}

	public static CompletableFuture<ByteArrayDataInput> sendPluginMessage(Player player, String channel, String... data) {
		CompletableFuture<ByteArrayDataInput> completableFuture = new CompletableFuture<>();

		if (player == null) {
			completableFuture.completeExceptionally(new IllegalStateException("Can't send plugin messages without a player"));
			return completableFuture;
		}

		Bukkit.getMessenger().registerIncomingPluginChannel(Skript.getInstance(), channel, new PluginMessageListener() {

			{
				ByteArrayDataOutput out = ByteStreams.newDataOutput();
				Stream.of(data).forEach(out::writeUTF);
				player.sendPluginMessage(Skript.getInstance(), channel, out.toByteArray());
			}

			@Override
			public void onPluginMessageReceived(String sendingChannel, Player sendingPlayer, byte[] message) {
				if (channel.equals(sendingChannel) && sendingPlayer == player && !completableFuture.isDone()) {
					completableFuture.complete(ByteStreams.newDataInput(message));
				}
			}

		});

		return completableFuture;
	}
  
  
  	@Override
	protected void execute(Event e) {
		String server = this.server.getSingle(e);
		if (server == null)
			return;
		// the message channel is case sensitive so let's fix that
		Utils.sendPluginMessage("BungeeCord", "GetServers")
				.thenAccept(response ->
					Stream.of(response.readUTF().split(", "))
							.filter(s -> s.equalsIgnoreCase(server))
							.findFirst()
							.ifPresent(s -> {
								for (Player player : players.getArray(e))
									Utils.sendPluginMessage(player, "BungeeCord", "Connect", s);
							})
				);
	}