websocket-chat | Websocket based group chat app built with socket.io | Websocket library

I am trying to build a gitlab pipeline to build a docker image from a java app. I have two artifacts, that I would like to pass between the build stages... One file (build_result.txt) is found an uploaded, but the other, (chat.jar) cannot be found. But, both files are in the same directory. Is there a size or extension limit for uploading files as artifacts?

I am trying to create a WebSocket client using React. I have adapted code from https://github.com/bitlabstudio/blogpost-react-websocket-chat/blob/master/frontend/src/Chat.js to create a WebSocket listener component as follows:

Getting error while running an image:

C:\Users\10649404\Desktop\spring-boot-websocket-chat-demo>docker run -p 5000:8080 ok 2019-04-29 07:10:58.660 INFO org.glowroot - Glowroot version: 0.10.12, built 2018-06-22 00:08:17 +0000 2019-04-29 07:10:58.673 INFO org.glowroot - Java version: 1.8.0_201

This is the jar file I am not getting. It says that missing lib/glowroot-embedded-collector.jar, even though it is present at the location.

I've tried to recreate WebSocket chat app (http://sparkjava.com/tutorials/websocket-chat) in Spark Java framework and stumbled upon a problem.

Frontend app couldn't connect to the server via WebSocket. I've looked into "Network" tab in the browser and there's a proper WebSocket call to a server but it respond with 500 code. There's no log on the server side, even though I've added System.out.println into @OnWebSocketConnect and @OnWebSocketClose functions. Why is that?

On every app launch I have an warning that says:

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.... for further details.

I don't think this is the issue but it might be worth mentioning.

I've added an exception catcher to the main class too, but it doesn't fire up:

I cloned a repo from Github and I would like to run it in the IntellIJ. The build tool used is Gradle and I have zero experience so far. The build.gradle file is provided below,

I am trying out Kotlin with SparkJava, and having trouble implementing the WebSockets routes. I am trying to follow the WebSockets example available on the SparkJava website (http://sparkjava.com/tutorials/websocket-chat), and whilst I can get the OnWebSocketConnect and OnWebSocketMessage elements to work, the OnWebSocketClose is not picked up.

I have implemented this in Java to double check that it is not a browser issues, and the Java implementation works fine...so this appears to be something specific to the way Kotlin is interpreting the OnWebSocketClose annotation.

My code looks like the following