JRuby 9000 on Mac OS X

JRuby. Ruby on the JVM.

Moore’s Law is about to run into a wall. Therefore, anything that software developers can learn about concurrency will be critical in coming years. Enter JRuby 9000.

What is JRuby?

JRuby is an implementation of the Ruby programming language that runs on the Java virtual machine (JVM). Advantages of running on the JVM include:

Installing JRuby 9000 on OS X

Grab the latest .tar file from JRuby Downloads and extract it by double-clicking on it. As of this writing, the latest version was jruby-bin-

Next, move the extracted files to /opt/jruby/. For example, if you downloaded the .tar file to your ~/Downloads directory, this command will rename the extracted directory to jruby/ in the process.

$ sudo mv ~/Downloads/jruby- /opt/jruby/


And finally, add the following line to ~/.bash_profile (or where ever you choose to set your $PATH variable).

export PATH="/opt/jruby/bin:$PATH"

Testing the JRuby 9000 installation

To test the JRuby 9000 installation, re-start your terminal or use $ source ~/.bash_profile. And then

$ jruby --version
jruby (2.2.0p0) 2015-01-20 d537cab Java HotSpot(TM) 64-Bit Server VM 25.25-b02 on 1.8.0_25-b17 +jit [darwin-x86_64]

$ which jruby


Why not RVM?

Given that I like RVM, why didn’t I simply use RVM to install JRuby 9000? Answer: The instructions for installing a pre-release version of JRuby via RVM were unclear to me. Extracting the executables and adding the directory to the $PATH was more grok-able. If your experience is different from mine, feel free to share in the comments below.

Next Steps

Next steps include experiments with concurrency. JRuby concurrency experiments with the 18-core Parallella look especially interesting. More to come.