Elixir/Erlang is slower than java for computationally expensive non tail optimized large struct operations maybe. For simple requests with ginormous thread counts the point of failure is going to get hit way sooner with Java than Erlang. If connecting directly to ETS/Mnesia/Dets instead of converting back and forth between an external persistence layer Erlang/Elixir can be amazingly fast. Doing Map Reduce type operations or performing massive data processing tasks in parallel Erlang/Elixirs is likely going to outperform Java. Anywhere where thread overhead is more critical than raw per thread performance Erlang/Elixir can perform better than alternative solutions.