This appears to be working mostly ok now. My console does not appear to render the puts output correctly but there's no error.

great! It's works now!
But still has bug for exsample:

# encoding : GBK
# frozen_string_literal: true

class CTT
	def 测试
		puts "#{__callee__} : first"
	end
	define_method(:测试){
		puts "#{__callee__} : second"
	}
end

obj = CTT.new
obj.测试
obj.send :测试

jruby 9.1.9.0-SNAPSHOT (2.3.3) 2017-04-28 ee137a8 Java HotSpot(TM) Client VM 25.131-b11 on 1.8.0_131-b11 +jit [mswin32-x86] output:

?? : first
测试 : second

MRI output:

测试 : second
测试 : second

@Personnel This is the other half of encoding work that @enebo is working on: making all identifiers use proper encoding too. In this case, it will need to get translated into the JIT naming of the compiled method as well as being properly represented in the method table.

Can you open a new bug for that, please?