I have a hard time with using Java to write micro-services. Even though lots of packages, such as Undertow, support non blocking I/O, a lot of the rest of the stack and the programmers that use it don’t know how to do NIO. What happens then is that the SRE/Ops team needs to configure large thread pools which consume lots of RAM just because multiplexing is I/O so difficult.

In comparison I can just start goroutines and Elixir processes for fast and simple I/O parallelism almost without thinking about it.