In what cases is it preferable to use the Set data structure?

The Set data structure is preferred in cases where it is necessary to store unique elements without duplicates and the order of elements is not important (or important, depending on the implementation).

Main scenarios for using Set:

• Removing duplicates from a collection.
• Checking for the presence of an element with high performance (usually, contains operations in Set are faster than in lists).
• Storing a set of unique values, such as unique identifiers, keywords, tags.

In Android and Java, the most commonly used implementations are HashSet (fast access without order) or LinkedHashSet (preserves insertion order).

Example:

Set<String> uniqueNames = new HashSet<>();
uniqueNames.add("Anna");
uniqueNames.add("Ivan");
uniqueNames.add("Anna"); // will not be added a second time

System.out.println(uniqueNames); // [Anna, Ivan]

Thus, Set is convenient when element uniqueness and efficient search are important.