Java Set Interface
The Set interface is part of the Java Collections Framework and is used to store a collection of unique elements.
Unlike a List, a Set does not allow duplicates, and it does not preserve the order of elements (unless you're using TreeSet or LinkedHashSet).
Common classes that implement Set:
HashSet- fast and unorderedTreeSet- sorted setLinkedHashSet- ordered by insertion
Tip: Use a
Setwhen you need to store unique values only.
Common Set Methods
| Method | Description |
|---|---|
add() |
Adds an element if it's not already in the set |
remove() |
Removes the element from the set |
contains() |
Checks if the set contains the element |
size() |
Returns the number of elements |
clear() |
Removes all elements |
Set vs. List
| List | Set |
|---|---|
| Allows duplicates | Does not allow duplicates |
| Maintains order | Does not guarantee order |
| Access by index | No index-based access |
Next, you'll explore the HashSet class in detail.
