What is the difference between the List and Set interfaces in the context of collections?

In Java, List and Set are collection interfaces with different properties:

• List — an ordered collection that allows duplicates. Elements have an index, and you can access elements by position.
• Set — a collection without duplicates; the order of elements is not guaranteed (unless using specific implementations like LinkedHashSet).

Example:

List<String> list = new ArrayList<>();
list.add("apple");
list.add("apple"); // duplicates are allowed

Set<String> set = new HashSet<>();
set.add("apple");
set.add("apple"); // second element will not be added

Thus, List is suitable when order matters and duplicates are allowed, while Set is used when you need to store unique elements without repetitions.