Java running in a container is somewhat amusing because of this. So you have a several solutions to the problem of agnostic packaging (java/jar/ear/war/etc) running inside another whole solution for agnostic packaging.
That’s just Java EE (now Jakarta) and Spring (when deployed to an application server). And indeed, these were containers before they were cool, with DB connections, pooling, it can connect to messaging services, etc. plus gives an environment where classes can easily do dependency injection, transactions, concurrency and many other things.
I don't think there's another way to ship custom certificate authorities without using containers? It's something you absolutely have to do around here if you want to interact with government APIs of any kind.
I relatively rarely work with Java and am probably mistaken.
I'm not saying containers aren't needed. Just that we keep trying to solve packaging and end up with more layers that have to duplicate large swaths of functionality. So we get java->containers->container orchestration, for example. The containers overlap some built-in java functionality, and so does the orchestration piece.