> Java could do it 20+ years ago, just upload your .WAR files to an application server.
Erlang could do it almost 40 years ago.
It can be used to upgrade applications at runtime without stopping the service. That works well in Erlang, it’s designed from the ground up for it. I know of a few places that used that feature.
Erlang seems like a joy to use. I feel a slight pang of regret that I haven't (yet) gotten to use it in my career. (I don't quite have the time or energy to play with it during my off hours, but it is on my list for someday.)
You might give Gleam [0] a try, which is advertised as "language you can learn in a day". It is type-safe, supports the BEAM and you can easily invoke Erlang and Elixir. Compiles to Erlang or Javascript.
This is kind of why I've never bothered to look at it - everyone /says/ it's a wonderful thing, but... nobody uses it in production, or hobbies (apart from the diehard fans)
It might see the light of day at some point in the future, but if the past is anything to go by...
I'm familiar with Whatsapp and its relationship with erlang (there's RabbitMQ as well, which I always forget when asked..)
But they're the only real case studies
If I were to say "Go", people can point to big projects like Docker, Kubernetes, etcd, Googles internal use, and a few others (Uber?)
Erlang just doesn't have that sort of buy in, which is concerning because it's been around longer than Go (as a FOSS language), heck it's been around longer than Python (but it was proprietary back then)
Speaking as someone that's never used it, that's got "don't bother unless you've got an academic interest in it" written all over it
Erlang could do it almost 40 years ago.
It can be used to upgrade applications at runtime without stopping the service. That works well in Erlang, it’s designed from the ground up for it. I know of a few places that used that feature.