In the process of debugging an unrelated issue, I came across an inconsistency between JRuby and CRuby: the #itself and #object_id methods are defined on BasicObject instead of Object.

> ruby -e "puts RUBY_DESCRIPTION; p BasicObject.instance_methods.sort"
ruby 2.2.0p0 (2014-12-25 revision 49005) [x86_64-darwin14]
[:!, :!=, :==, :__id__, :__send__, :equal?, :instance_eval, :instance_exec]
> jruby -e "puts RUBY_DESCRIPTION; p BasicObject.instance_methods.sort"
jruby 9.0.0.0.pre1 (2.2.0p0) 2015-01-20 d537cab Java HotSpot(TM) 64-Bit Server VM 24.51-b03 on 1.7.0_51-b13 +jit [darwin-x86_64]
[:!, :!=, :==, :__id__, :__send__, :equal?, :instance_eval, :instance_exec, :itself, :object_id]

WARNING

I am not an expert ☕ programmer nor am I particularly familiar with the JRuby codebase, however I’ve made an attempt to fix this issue myself, as it appears to be mostly a ✂️ and 🍝 job.

I’ve also attempted to add a test to prevent this behavior from regressing, however I may have put it in the wrong place, as JRuby appears to have multiple test suites.

I’ve also taken the liberty to remove the Object#id method, which was deprecated when Ruby 1.9 was released and removed from CRuby before version 1.9 was released (search for rb_obj_id_obsolete).