One shared JVM for maximum performance!
It can also share db connection pools, caches, etc. among those applications!
Wow!
Because a lot of production software is half-baked. If you have to hand over an application to an operations team you need documentation, instrumentation, useful logging, error handling and a ton of other things. Instead software is now stuffed into containers that never receive security updates, because containers make things secure apparently. Then the developers can just dump whatever works into a container and hide the details.
To be fair most of that software is also way more complex today. There are a ton of dependencies and integrations and keeping track of them is a lot of work.
I did work with an old school C programmer that complained that a system we deployed was a ~2GB war file, running on Tomcat and requiring at least 8GB of memory and still crashed constantly. He had on multiple occasions offered to rewrite the how thing in C, which he figured would be <1MB and requiring at most 50MB of RAM to run. Sadly the customer never agreed, I would have loved to see if it had worked out as he predicted.