Showstopper issue with JRuby ?

After some break, I dusted off the Ruby to try out one interesting idea Peter presented yesterday that literally ASKS for Rails. So I grabbed the latest and greatest RubyNetBeans from Ruby Hudson. For some reason it stopped updates on January 26th so the latest version I have got was build 6327. It is bundled with JRuby 1.1RC1 and the Rails version that comes preinstalled is 1.2.6. Using the menu Tools -> Ruby Gems, they can be easily upgraded to latest and greatest 2.0.2.

The trouble begins when you want to install database connectivity gems such as sqlite3-ruby. The installer fails with the message:


trying to install

INFO:  `gem install -y` is now default and will be removed
INFO:  use --ignore-dependencies to install only the gems you list
Building native extensions.  This could take a while...
extconf.rb:1: no such file to load -- mkmf (LoadError)
ERROR:  Error installing sqlite3-ruby:
    ERROR: Failed to build gem native extension.

/Users/miro/Applications/<a href="http://RubyNetBeans.app/Contents/Resources/nbrubyide/ruby1/jruby-1.1RC1/bin/jruby" class="linkification-ext" title="http://RubyNetBeans.app/Contents/Resources/nbrubyide/ruby1/jruby-1.1RC1/bin/jruby">RubyNetBeans.app/Contents/Resources/nbrubyide/ruby1/jruby-1.1RC1/bin/jruby</a> extconf.rb install sqlite3-ruby --no-rdoc --no-ri --include-dependencies --version &gt; 0

Gem files will remain installed in /Users/miro/Applications/<a href="http://RubyNetBeans.app/Contents/Resources/nbrubyide/ruby1/jruby-1.1RC1/lib/ruby/gems/1.8/gems/sqlite3-ruby-1.2.1" class="linkification-ext" title="http://RubyNetBeans.app/Contents/Resources/nbrubyide/ruby1/jruby-1.1RC1/lib/ruby/gems/1.8/gems/sqlite3-ruby-1.2.1">RubyNetBeans.app/Contents/Resources/nbrubyide/ruby1/jruby-1.1RC1/lib/ruby/gems/1.8/gems/sqlite3-ruby-1.2.1</a> for inspection.
Results logged to /Users/miro/Applications/<a href="http://RubyNetBeans.app/Contents/Resources/nbrubyide/ruby1/jruby-1.1RC1/lib/ruby/gems/1.8/gems/sqlite3-ruby-1.2.1/ext/sqlite3_api/gem_make.out" class="linkification-ext" title="http://RubyNetBeans.app/Contents/Resources/nbrubyide/ruby1/jruby-1.1RC1/lib/ruby/gems/1.8/gems/sqlite3-ruby-1.2.1/ext/sqlite3_api/gem_make.out">RubyNetBeans.app/Contents/Resources/nbrubyide/ruby1/jruby-1.1RC1/lib/ruby/gems/1.8/gems/sqlite3-ruby-1.2.1/ext/sqlite3_api/gem_make.out</a>

The missing file mkmf.rb is indeed missing from the JRuby distribution. This is entered as a bug in JIRA 1306 with resolution ‘Won’t fix’. Tough luck.

I understand the reasons and motivation for this decision – the JRuby team decided not to support native extensions in Gems, to keep the platform Java only. I also understand that in this particular case, there are workarounds – using ActiveRecord-DBC gem and JDBC drivers for the database will most likely work. Unfortunately, this decision makes choice of JRuby as platform very questionable.

I really liked JRuby for the comfort of having platform that is portable and safely wrapped within boundaries of the good old trusted JVM. I feel much more comfortable maintaining possibly several different versions of JRuby and corresponding Gems sets than maintaining same several configurations on the OS level and sudo-ing just to install Gems. I was more that happy to trade the lack of speed for this security.

The two main attractions of Ruby (from my point of view) are elegant, powerful language with beautiful syntax as well as sheer amount of code available as Gems to be reused. With the bug 1306, many of this code may not be available for JRuby – unless Gem authors make specific provisions for Java version of the Gem. I cannot think how this is a good idea and certainly not a good news for the future of the language.

One way out is use native Ruby interpreter, of course and make sure you do not mess up your installation by trying out new things. This does not allow the easy way into enterprise that JRuby was promising – by being basically ‘just another jar’ and running on Tomcat.
The other way out is to reconsider the Groovy. I still do not enjoy the syntax anywhere close to Ruby, but every Groovy class is Java class, there is no need for artificial bridges. It has own clone of Rails – GRails – that seems to provide lots of Rails magic and goodies and is based on Spring which I am very familiar and quite happy with. I still do not know whether the amount of “gems” in Groovy world is in the same league as Ruby (which is still limited compared to Python or even CPAN Perl bonanza) – but as long as I can find that what I need, it may be just enough.

For now, I will revert back to Ruby (no time to start learning Groovy+Grails), but I definitely will look at it later on.

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Explore posts in the same categories: groovy, Java, jruby, ruby, rubyonrails

One Comment on “Showstopper issue with JRuby ?”


  1. Yes, it’s unfortunate we can’t support the native extensions right now, but we hope to provide a migration path in the future. And what’s more, we’re very interested in helping folks port appropriate libraries to their Java equivalents. In this case, you could use JavaDB, a nice small embedded pure-Java database, or you could try to wire up the SQLite JDBC drivers. Hope to hear from you on either of those options sometime soon.


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