# jRuby Sanity Check

**URL:** <https://www.ruby-forum.com/t/jruby-sanity-check/144943>\
**Category:** Rails\
**Created:** [August 4, 2008, 3:59pm UTC](https://www.ruby-forum.com/t/jruby-sanity-check/144943 "2008-08-04T15:59:25Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![blinking\_bear](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/a9a28c/32.png) [@blinking\_bear](https://www.ruby-forum.com/u/blinking_bear)\
**Post date:** [August 4, 2008, 3:59pm UTC](https://www.ruby-forum.com/t/jruby-sanity-check/144943/1 "2008-08-04T15:59:25Z")

</div>

Hey all,

We’re building a beta for a large organization that is primarily a Java  
shop. Ideally, we’d like to build the initial beta in Rails and run it  
like  
a traditional rails app. However, it would be great to at some point be  
able to run it using jRuby on the JVM and possible integrate with their  
existing systems and/or drop into Java for some performance areas. From  
what I’ve read about jRuby the following appears to be true but I could  
be  
totally wrong:

1. You can take an existing Rails app and, assumming all tests pass,  
just  
run it as as on JRuby.
2. You can ‘drop into Java’ if need be to improve perforamnce of parts  
of  
an application

feel free to tell me if I’m way off

---

<div class="post-metadata">

**Author:** ![blinking\_bear](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/a9a28c/32.png) [@blinking\_bear](https://www.ruby-forum.com/u/blinking_bear)\
**Post date:** [August 4, 2008, 5:05pm UTC](https://www.ruby-forum.com/t/jruby-sanity-check/144943/2 "2008-08-04T17:05:44Z")

</div>

for the most part yes. I think the biggest snag you will hit is if your  
rails app depends on any gems with only native C extensions, Jruby does  
not  
support those. For example, libxml wont work in JRuby along with any  
other  
native extension gems. That is the first thing to vet out.

Other than that, using warbler to deploy a war file has been pretty  
painless  
for us so far running under Tomcat 5.5.

Adam