I'll also point out, I'd much prefer a default of Elixir, than of Java.
Why? Because most of my problems are things Elixir can solve well, and Java can solve moderately well, after a bunch of pain and tweaking. Default to the thing that can solve most of your problems well, and pick a different tool when needed, rather than default to the thing that can solve all of your problems moderately well, and you never pick anything else, and so never have any elegant, quickly built yet well designed, solutions.
Why? Because most of my problems are things Elixir can solve well, and Java can solve moderately well, after a bunch of pain and tweaking. Default to the thing that can solve most of your problems well, and pick a different tool when needed, rather than default to the thing that can solve all of your problems moderately well, and you never pick anything else, and so never have any elegant, quickly built yet well designed, solutions.