# JRuby

13 Hacker News commenters recommended JRuby and 2 criticized it, November 2025 to November 2026. It was recommended in 9 of 13 months. It meets the Hacker Approved badge rule.

**Verdict:** Ruby running on the Java Virtual Machine, with access to Java libraries and full concurrency. Caveat: inline types are missed, and it is not quite identical to Ruby.

## Why people recommend it

- Runs Ruby on the JVM (2 comments): "runs Ruby on a Java Virtual Machine with full concurrency and Ahead Of Time compilation" ([source](https://news.ycombinator.com/item?id=49712499)) "I was surprised just how good JRuby was at working with all the same libraries as Java" ([source](https://news.ycombinator.com/item?id=46160647))
- Viable alternative to MRI (2 comments): "I love that Ruby has 3 high quality implementations in MRI, JRuby and Truffleruby." ([source](https://news.ycombinator.com/item?id=46622542)) "JRuby is way more viable than Jython ever was" ([source](https://news.ycombinator.com/item?id=48225385))

## What people warn about

- Missing inline types (1 comments): "although inline types are sorely missed still" ([source](https://news.ycombinator.com/item?id=49395529))

## Alternatives hackers recommend

- [Spinel Ruby compiler](https://hackerapproved.com/p/spinel.md): 12 recommend
- [TruffleRuby](https://hackerapproved.com/p/truffleruby.md): 10 recommend
- [mruby](https://hackerapproved.com/p/mruby.md): 8 recommend

## Cite as

Hacker Approved, "JRuby", https://hackerapproved.com/p/jruby/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).