This week's book giveaway is in the OCAJP forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide 1Z0-808 and have Jeanne Boyarsky & Scott Selikoff on-line! See this thread for details.
But Lists support duplicate values and ordering, which Sets don't. So you are losing information by putting things into a Set, which you cannot retrieve. If there is any way you can put them into a List at the outset, you can retain that information.