The kwargs handling for the following code appears to be too aggressive, and results in the HashMap getting converted into a normal Ruby Hash:

h = java.util.HashMap.new
class X
  def blah(*args, **kwargs)
    args
  end
end
class Y < X
  def blah(*args)
    super
  end
end
arr = Y.new.blah(h)
p arr[0].class # Hash, should be java.util.HashMap

This is the cause of recent CI failures in spec:ji, due to the recent rspec-expectations 3.9.3 release. The specific change was rspec/rspec-expectations@23c1de7 as part of rspec/rspec-expectations#1187 which appears to have been made to better support keyword arguments in the method_missing based matchers (like be_equal?, which is what started failing in our JI specs).

I will pin our Gemfile to rspec-expectations 3.9.2 to get the build green again, but this needs to be addressed for 9.3 at least and possibly 9.2.14 as well.