Singleton Design Pattern in Java | Lazy Initialization, Synchronization & Double-Checked Locking
The Singleton Design Pattern in Java is one of the most commonly asked design pattern in core Java interview questions — and one of the most misunderstood when it comes to real-world production environments. In this video, we break down the singleton design pattern in Java end-to-end, from a private constructor all the way to double-checked locking.
Building a singleton class in Java looks simple on the surface — until you throw multithreading in Java into the mix. This guide covers every critical layer of the singleton pattern: starting with the basic eager approach, moving into lazy initialization, and then tackling the hard problem — why the naive singleton design pattern fails in a multithreaded environment and how to fix it the right way.
Most developers' first instinct to make the singleton thread-safe introduces a new problem — one that quietly kills performance under concurrent load. The synchronized keyword isn't wrong, but where you apply it makes all the difference. Watch the video to see exactly where that line is drawn.
Whether you're brushing up on java design patterns for your next backend role or specifically preparing for concurrency and multithreading in java interview rounds, this is your complete reference guide.
🔑 What You'll Learn:
✅ Why controlling object creation is the cornerstone of the singleton class in Java
✅ How a class exposes exactly one instance — and why the method signature is more important than it looks
✅ The hidden flaw in the basic singleton approach that breaks under real application load
✅ How lazy initialization improves efficiency — and the race condition it quietly introduces
✅ Why multithreading in Java is the biggest threat to a naive singleton pattern
✅ Why synchronizing the entire getInstance() method hurts performance — and how block-level synchronization solves it
✅ How double-checked locking delivers thread safety without killing performance
✅ Real-world singleton use cases that signal senior-level thinking in interviews
📌 This video is part of the Design Patterns in Java series — a critical pillar in software design patterns for backend developers cracking product and service-based company interviews. If multithreading in java interview questions are on your prep list, understanding how singleton behaves under concurrent access is non-negotiable.
🔔 Subscribe for weekly deep-dives on java design patterns, Spring Boot, core Java, and everything you need to ace your next tech interview.
To access the code: Clone below mentioned repository and checkout to branch : singleton-pattern
Github Link: https://github.com/TheCuriousCoder-sg...
Instagram :
/ the.curious_coder
#SingletonDesignPattern #SingletonPattern #DesignPatternsInJava #JavaDesignPatterns #MultithreadingInJava #ThreadSafety #DoubleCheckedLocking #JavaInterviewQuestions #CoreJavaInterviewQuestions #LowLevelDesign #Java #JavaProgramming #BackendDevelopment #CuriousCoder
In questa pagina del sito puoi guardare il video online Singleton Design Pattern in Java | Lazy Initialization, Synchronization & Double-Checked Locking della durata di ore minuti seconda in buona qualità , che l'utente ha caricato The Curious Coder 05 giugno 2026, condividi il link con amici e conoscenti, su youtube questo video è già stato visto 2,039 volte e gli è piaciuto 89 spettatori. Buona visione!
