The JVM's historical slow startup was JRuby's biggest usability complaint: 5–10 years ago a rake task that took 500ms–1s on C Ruby could take 4–5s on JRuby, enough to disrupt iterative Rails/CLI workflows. Today JRuby's baseline startup is well under a second (~400ms), and heavy rake tasks/Rails commands loading many gems are ~1–1.5s. Integrating new JVM features (pre-optimized code, Lilliput object shrinking) continues to close the gap.