What are the main interfaces in the Java Collections Framework?

The Java Collections Framework (JCF) provides a set of interfaces and classes that facilitate the storage and manipulation of groups of objects. The main interfaces in the JCF include:

1. Collection

The root interface in the collection hierarchy. It represents a group of objects known as elements.

2. List

A collection that maintains an ordered sequence of elements. Lists allow duplicate elements.

List list = new ArrayList<>();

3. Set

A collection that does not allow duplicate elements. It models the mathematical set abstraction.

Set set = new HashSet<>();

4. Queue

A collection designed for holding elements prior to processing. It follows the First-In-First-Out (FIFO) principle.

Queue queue = new LinkedList<>();

5. Map

An object that maps keys to values, where each key is unique. Maps do not implement the Collection interface.

Map map = new HashMap<>();

Conclusion

The Java Collections Framework provides essential interfaces that help developers manage groups of objects effectively. Understanding these interfaces is crucial for efficient data manipulation and storage in Java applications.