Java Collections API

The Java Collections Framework (JCF) is a set of interfaces and classes that provide efficient ways to store, manipulate, and process data in Java. It is part of the java.util package and provides implementations for lists, sets, maps, queues, and more.

Collection Framework Hierarchy:

Java Collections API is structured as follows:

Collection Interface (Root Interface)

🔹 List → Ordered collection (e.g., ArrayList, LinkedList)

🔹 Set → Unique elements only (e.g., HashSet, TreeSet)

🔹 Queue → FIFO (First-In-First-Out) (e.g., PriorityQueue, LinkedList)

Map Interface (Separate from Collection)

🔹 Map → Key-Value pairs (e.g., HashMap, TreeMap, LinkedHashMap)

Key Interfaces & Implementations: