Theine

Theine is a Rails application pre-loader designed to work on JRuby. It is similar to Zeus, Spring and Spork. The problem with Zeus and Spring is that they use fork which doesn't work on JRuby.

  time rails runner "puts Rails.env"
  48.31s user 1.96s system 242% cpu 20.748 total  # normal
  time theine runner "puts Rails.env"
  0.12s  user 0.02s system 32%  cpu 0.449  total  # Theine

Docs https://theine2.readthedocs.io/en/latest