While we're talking about who is who -- the parent poster is Jed Smith; he's a sysadmin and disgruntled former CoreOS employee. I'd take what he says with more than a grain of salt.

Personal attacks are not allowed on HN, nor single-purpose accounts. Novelty accounts for personal attacks are right out, so we've banned this one.

"Scala in particular with its immutability generates a lot of garbage if you are not careful, and we were constantly fighting GC pressure (and, indirectly, our achievable concurrency and efficiency) at a household name Scala app. The number of JVM developers who are aware of this and capable with the memory subsystem -- i.e., off-heap strategies such as that used in Flink (relevantly) and some of the clever speedups in netty -- are dwarfed by the number of JVM developers in the whole, so you really need someone who understands these problems to efficiently scale a JVM language."

Jed, once again you are laying claim to experience you do not have. If you ever once had touched Scala at Foursquare it would be a different story. This is just a bunch of tired platitudes.