"It is easy to notice that in Java, one might have implemented infinite number of for loops trying to do such lookups using iterators." ?? val list3 = list1 :

"It is easy to notice that in Java, one might have implemented infinite number of for loops trying to do such lookups using iterators." ?? val list3 = list1 ::: list 2 // returns a new list of 6 elements final list3 = new ArrayList(list1).addAll(list2); list3.drop(2) //return a new list without first 2 elements new ArrayList(list3.subList(2)); list3.filter(s => s > 4) //return a list with elements 5 and 6 new ArrayList(list3.subList(4)); Also the Java versions use standard convenience methods which seems preferable to language features since anyone can re-implement them, or add new ones. Plus the copy-on-mutate behaviour is optional.