Hi there - no problem. Feel free to ask any question you'd like. You're not going to hurt our feelings and we'd rather clarify any confusion than let it linger

Hi there - no problem. Feel free to ask any question you'd like. You're not going to hurt our feelings and we'd rather clarify any confusion than let it linger and manifest into some weird FUD. On that note, we're quite active in the JRuby IRC and gitter rooms, so you ever have a question you want answered more real time, feel free to hop in and ask away. The "can of worms" comment wasn't meant to be pejorative -- only that there's a lot to the problem and it's not exactly clean. There simply isn't an extension API in JRuby. There's just the JRuby JAR and whatever is publicly reachable. The situation today is there are two backends available for JRuby: the standard IR-based one and the Truffle-based one. The two backends make use of shared infrastructure, but are otherwise quite distinct. E.g., both backends have different object models for Ruby-level classes & objects. Take Ruby strings for instance. They use a shared abstraction for the underlying implementation, but there's no shared interface -- it's all composition. Creating a Ruby string in a Java extension means importing org.jruby.RubyString and creating an instance of it. JRuby+Truffle represents strings differently, so creating a string that way presents a problem. The simplest thing to do is translate everything between the two runtimes, but that incurs a lot of overhead, unnecessary object allocations, and grossly limits our ability to optimize calls. The harder solution is to provide a JRuby+Truffle implementation of the API, but given its current lack of definition, we'd have to support the de facto API for 100% compatibility and the de facto API is massive. We're working with the JRuby core team to annotate a portion of the API to be used for extensions, at which point the problem becomes much easier to manage. FWIW - Prior to joining Oracle Labs I made a big gamble on JRuby for my start-up (Mogotest). I love JRuby and have been working with it for years outside of my current gig. I'd love to see JRuby+Truffle simply work with Java extensions, because they can be really nice (JDBC + Sequel is amazingly fast). Unfortunately, it's just a messy issue at the moment.