Customizable build options for JRuby
Change effective on 07 May 2015
Heroku’s support for JRuby now includes customization of the JRUBY_OPTS environment variable at build time. The default value for versions after and including JRuby 1.7.12 is --dev, which optimizes for short one-off processes. For prior versions the default value is the expanded version of this setting, which is:
-Xcompile.invokedynamic=false -Xcompile.mode=OFF -J-XX:+TieredCompilation -J-XX:TieredStopAtLevel=1
However, this can be customized by setting the config variable JRUBY_BUILD_OPTS, which will override JRUBY_OPTS at build time only. At runtime, the default value of JRUBY_OPTS will remain as -Xcompile.invokedynamic=false.
For more information of JRuby, see Heroku’s Ruby Support on the Dev Center.