Imho, the java aspect of it matters much less than the backend concepts. Are you already familiar with those ?

There’s quite a lot of stuff to learn on the backend and it really depends on which layer you want to focus on. If you’re interested in developing business services then i would recommend writing a restful API (for example for a to-do app) with spring boot and your preferred flavor of SQL database. That covers a lot already. From there you can look at how to scale performance up (caching, queuing, asynchronous).

The article makes a good job of explaining the requirement but it doesn’t actually explain why expanding OTEL to support a jdbc exporter is not the best solution. Other than “it’s not straightforward”.

Tracing is not as trivial as it seems and I would be warry of rolling out a bespoke solution.

A few questions that come to mind:

• what do you mean when you say the traces should be “stateless”?
• why a SQL database? Traces typically have evolving schemas
• why can’t this be done with a straightforward Filter implementation?