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

As @mmyers states, Collection includes Set, as well as List.

When you declare something as a Set, rather than a Collection, you are saying that the variable cannot be a List or a Map. It will always be a Collection, though. So, any function that accepts a Collection will accept a Set, but a function that accepts a Set cannot take a Collection (unless you cast it to a Set).