The entire HashiCorp stack and Cockroachdb comes to mind. I’m sure there are things that are much more complex in the world, but they do some fairly heavy lifting.
> especially not cross-platform
I find it drastically simpler to download a single binary for each platform I need to deploy to(macOS,Linux,FreeBSD) than it is to get a consistent Java environment setup on those same platforms.
I think the big difference is that Java projects TEND to be more 'up front' about their configuration options, with shipped default files with a lot of the options already set to some default value, while projects like the ones you mentioned require you to look up every property yourself and set it to something if you want to change it from the default.
Are you saying that Java projects tend to have more sane defaults and come bundled with more out of the box?
The last Java project I had to deploy was ElasticSearch/Kibana, and there was a LOT of configuration needed that required consulting a lot of disparate documentation.