Design Scheduled Thread Pool Executor : Concurrency LLD Interview

Ever wondered how tech giants like Uber, LinkedIn, and Rubrik handle millions of scheduled tasks? In this video, we go beyond theory and actually build our own Custom ScheduledThreadPoolExecutor from scratch using Java. We break down the magic behind the DelayQueue, explore how worker threads poll for tasks, and demystify the critical difference between scheduleAtFixedRate and scheduleWithFixedDelay. If you want to understand concurrency at a deep, engineering level, this is the masterclass you need. We cover everything from the architecture of a production-ready scheduler to the internal logic of the ScheduledTask class. You’ll learn how to manage thread factories, handle task rescheduling with nanosecond precision, and implement a robust shutdown hook. This is not just an algorithm—it’s a system design test that separates senior engineers from the rest. 🚀 Key Takeaways: How to use DelayQueue as the backbone for task scheduling. Implementing the Delayed interface for precise execution timing. The difference between Fixed-Rate and Fixed-Delay scheduling. Building a thread pool that manages periodic and one-time tasks. If you found this deep dive helpful, please smash that like button, subscribe for more system design content, and comment below with what you want us to build next! #Java #Concurrency #SystemDesign #Programming #Multithreading #TechInterview #SoftwareEngineering #Coding #BackendDevelopment #UberTech #LinkedInEngineering #Rubrik #ScheduledThreadPoolExecutor #DelayQueue #LearnJava