scala version

gistfile1.scala

class Person(var firstName: String, var lastName: String, var address: Address) {
	def this() = this(null, null, null)
}
class Address(var city: String, var street: String) {
	def this() = this(null, null)
}
val persons = getAListSomewhere();
val filtered = persons.filter(_.address.city == "Kyiv") 
val adresses = persons.map(_.address).toSet