Patch that would be helpful to ethers if it gets into jruby 1.7.5.

gistfile1.txt

JRuby 1.5 cleanup

# COMITTED UPSTREAM - But leaving here in case we need refernce.
# There was some implementation changed, and I didn't have tests to catch everything
# this is here until we can get it commited upstream
module JRuby
  class JavaSignature
    # FIXME: Can make this accept whole list too if that is actual contract
    # FIXME: Can be literals too
    def as_java_type(string)
      type = primitive? string
      return type if type

      # If annotation makes it in strip @ before we try and match it.
      if string.is_a?(String)
        string = string[1..-1] if string.start_with? '@'
      end

      eval make_class_jiable(string)
    end

    def make_class_jiable(string)
      if string.is_a?(Java::OrgJrubyAstJava_signature::ReferenceTypeNode)
        # Basically, if a package segment is capitalized, it's assumed to be a class in the package name.
        name = string.getFullyTypedName()
        klass_names,package_parts = name.split(".").partition{|n| n =~ /^[A-Z]/ }
        "#{package_parts.join(".")}.#{klass_names.join("::")}"
      elsif string.is_a?(Java::OrgJruby::RubyClass)
        return string.class.to_s
      else
        new_list = []
        string.split(/\./).inject(false) do |last_cap, segment|
          if segment =~ /[A-Z]/
            if last_cap
              new_list << "::" + segment
            else
              new_list << "." + segment
            end
            last_cap = true
          else
            new_list << "." + segment
            last_cap = false
          end
        end
        "Java::#{new_list.join("")[1..-1]}"
      end
    end
  end
end

class Class
  def add_field_signature(name, type)
    self_r = JRuby.reference0(self)

    signature = JRuby::JavaSignature.new(nil, nil)
    java_return_type = signature.as_java_type(type)

    self_r.add_field_signature(name, java_return_type.java_class)
  end

end

@tarcieri

JavaSignature may actually be committed upstream, I can't figure out what my comment is saying.

add_field_signature is definitely busted, it only works for primitives, this patch works for objects as well.