ji_kwargs_to_hash.rb

require 'java'

class WrappedHash < Hash
  def initialize(value)
    @value = value
  end
  
  def [](key)
    @value[key]
  end  
end

class Java::java::util::HashMap
  def to_hash
    WrappedHash.new(self)
  end
end

h = java.util.HashMap.new
h["one"] = 2

def foo(one:)
  p one
end

foo(**h)