@SpringBootApplication
@LineMessageHandler
public class DemoApplication{

    public static void main(String[] args) throws IOException {

        SpringApplication.run(DemoApplication.class, args);
    }

    @Autowired
    private LineMessagingService lineMessagingService;

    @EventMapping
    public void handleTextMessageEvent(MessageEvent<TextMessageContent> event) throws Exception {

    String channelTtoken = System.getenv("LINE_BOT_CHANNEL_TOKEN");
    String fixieUrl = System.getenv("FIXIE_URL");
    String[] fixieValues = fixieUrl.split("[/(:\/@)/]+");
    String fixieUser = fixieValues[1];
    String fixiePassword = fixieValues[2];
    String fixieHost = fixieValues[3];
    int fixiePort = Integer.parseInt(fixieValues[4]);

    OkHttpClient.Builder clientBuilder = new OkHttpClient.Builder();
    Authenticator proxyAuthenticator = new Authenticator() {
        @Override public Request authenticate(Route route, Response response) throws IOException {
            String credential = Credentials.basic(fixieUser, fixiePassword);
            return response.request().newBuilder()
                .header("Proxy-Authorization", credential)
                .build();
        }
    };

    Proxy prx = new Proxy(Proxy.Type.HTTP, new InetSocketAddress(fixieHost, fixiePort));
    clientBuilder.proxy(prx).proxyAuthenticator(proxyAuthenticator);

    ReplyMessage replyMessage = new ReplyMessage(event.getReplyToken(),
        Collections.singletonList(new TextMessage(event.getSource().getUserId())));

    retrofit2.Response<BotApiResponse> response =
        LineMessagingServiceBuilder
                .create(channelTtoken)
                .okHttpClientBuilder(clientBuilder)
                .build()
                .replyMessage(replyMessage)
                .execute();
    System.out.println("response: " + response.code() + " " + response.message());

    final BotApiResponse apiResponse = lineMessagingService
        .replyMessage(new ReplyMessage(event.getReplyToken(),
                Collections.singletonList(new TextMessage(event.getSource().getUserId()))))
        .execute().body();
    System.out.println("Sent messages: " + apiResponse);
}

@EventMapping
public void defaultMessageEvent(Event event) {
    System.out.println("event: " + event);
}