How to run Ruby 2.0 with JRuby 1.7?

For a specific script, you can use the --2.0 option:

jruby --2.0 -S rails s

For setting 2.0 as the default value, set JRUBY_OPTS:

export JRUBY_OPTS=--2.0

You can also set the value in ~/.jrubyrc:

compat.version=2.0

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