How to distinguish a Set data structure from a Map in terms of their usage and characteristics?

Set and Map are two different data structures in Java, serving different purposes:

• Set is a collection of unique elements. It stores only keys (elements), without values. The main goal is to store a set of unique objects without duplicates. Example: a set of unique users, unique words, etc.

• Map is a collection of key-value pairs. Each key is unique, but it is associated with a value. It is used when you need to store data as a correspondence, for example, a username and its profile.

Example usage:

Set<String> uniqueNames = new HashSet<>();
uniqueNames.add("Alice");
uniqueNames.add("Bob");

Map<String, Integer> nameToAge = new HashMap<>();
nameToAge.put("Alice", 30);
nameToAge.put("Bob", 25);

Thus, Set is simply a collection of unique elements, and Map is a dictionary where each key corresponds to a value.