Every swing tutorial out there starts with a good old:

  c = new Container()
  w = new Widget()
  c.add(w)
  w.addActionListener(
    …200 bytes of a functor boilerplate…
  )

Also I don’t know java well, but variable/keyed arguments and closures like in python do not exist there, to my knowledge.

Am I missing something, or maybe you meant something else?