require "java"
require "DuckTyping.jar"
duck = Java::org.edubkendo.ducks.Duck.new
chicken = Java::org.edubkendo.ducks.Chicken.new
Java::org.edubkendo.ducks.DuckTyping.duck_typing(duck)
Java::org.edubkendo.ducks.DuckTyping.duck_typing(chicken)
# >> Quack!
# >> Um, cluck, cluck!