Integrating java servlet backend with react front end

[airmd]

I'm building a very simple portfolio project on google cloud shell editor. My project is a Java-based web application that utilizes Google Cloud Platform and Google App Engine to serve content. It uses Maven for dependency management and Jetty as a web server. It's just a simple portfolio website with a Java Servlet back-end. I'm working on integrating a React front-end into the existing application to create a more interactive and visually appealing user interface. I was able to install the dependencies I need and created my react app and everything works fine. I'm now trying to deploy my app, and after setting the target and deploying I get a 404 error when I try to view the website. The logs show it's working fine and that it's trying to get data from the right path of the build of the react app I specified, so I don't really understand what's going on. Also when I change the target back to the original frontend(not the react), my website renders that frontend and I see. But it can't seem to render the website from the build of the react app.

I've been working on this for the past 6 hours and it's driving me crazy. I was hoping if anybody here is experienced in google cloud platforms and integrating react front ends to a java servlet backend could help me figure out what's going on.

[kolban]

I'd suggest we draw a diagram of where all the piece parts sit.  No need (and not recommended) to name real project names or real IPs or real URLs ... but consistent made up ones will be fine.   I think I'd like to understand the core steps you have performed to publish your app and what URL (logically) you are using.  If you are getting a 404 error, than is (I believe) that the requested resource is not found BUT something is serving up that 404.  Do we have proof/evidence that the request is getting to AppEngine and Jetty?  Can we switch on any diagnostics to get more logging out of the system?  Is anything being served up?

What is a "portfolio project"?