Location: IGSAAS
Date: 25 May, 2024
Sharing By: Chit Senghoung - Backend Engineer

Java Collections is a framework that provides a set of classes and interfaces for storing and manipulating groups of data as a single unit, known as a collection.

Goal of collections are provided as set standard of data structure to allow manage group of data and performant code in java. Import collection from java.util package.

Java Collections is a framework that provides a set of classes and interfaces for storing and manipulating groups of data as a single unit, known as a collection, with the goal of offering standardized data structures for efficient data management and performance in Java, all available through the java.util package. Special thanks to Mr. Chit Senghoung for his invaluable contributions sharing.

Java Collections Framework: Key Features

1. Unified Architecture

• Interfaces: Core interfaces (Collection, List, Set, Queue, Map) provide flexibility and reusability.
• Implementations: Concrete classes like ArrayList, LinkedList, HashSet, TreeSet, HashMap, TreeMap.

2. Common Methods

• Basic Operations: add(), remove(), size(), contains().
• Bulk Operations: addAll(), removeAll(), retainAll(), clear().

3. Traversal

• Iterator: Methods to traverse collections (hasNext(), next(), remove()).
• Enhanced for-loop: Simplifies iteration.
• Spliterator: Supports parallel processing.

4. Sorting and Searching

• Comparable and Comparator: Define natural and custom orderings.
• Collections Utility Class: Methods for sorting (sort()), searching (binarySearch()).

5. Synchronization

• Thread-Safe Collections: Vector, Hashtable.
• Concurrent Collections: ConcurrentHashMap, CopyOnWriteArrayList, BlockingQueue.

6. Streams and Functional Programming

• Stream API: Functional-style operations (filter(), map(), reduce()).
• Lambdas and Method References: Concise syntax for anonymous functions.

7. Performance

• Time Complexity: Different performance characteristics (ArrayList vs. LinkedList).
• Space Complexity: Efficient memory use with dynamic resizing.

8. Immutability

• Unmodifiable Collections: Methods to create immutable collections (Collections.unmodifiableList()).

9. Specialized Collections

• PriorityQueue: Elements ordered by natural or custom comparator.
• Deque: Double-ended queue (ArrayDeque, LinkedList).

10. Generics

• Type Safety: Generics ensure type safety, reducing runtime errors.