when to use Set vs. Collection?

Question

Is there any practical difference between a Set and Collection in Java, besides the fact that a Collection can include the same elemen

Answer 1

One other thing to consider... Sets have extra overhead in time, memory, and coding in order to guarantee that there are no duplicates. (Time and memory because sets are usually backed by a HashMap or a Tree, which adds overhead over a list or an array. Coding because you have to implement the hashCode() and equals() methods.)

I usually use sets when I need a fast implementation of contains() and use Collection or List otherwise, even if the collection shouldn't have duplicates.