Java Collections Framework

The Java Collections Framework provides a unified architecture for storing and manipulating groups of objects.

Key Interfaces

• List — Ordered collection (ArrayList, LinkedList)
• Set — No duplicates (HashSet, TreeSet)
• Map — Key-value pairs (HashMap, TreeMap)
• Queue — FIFO processing (PriorityQueue, ArrayDeque)

When to Use What

Use ArrayList for random access, LinkedList for frequent insertions/deletions at both ends.