Hi, I'm Nikhil. 👋 I've spent 7+ years building event-driven platforms and high-throughput systems at scale — the kind where a single race condition at 2 AM means millions in lost transactions. Most engineers "learn" concurrency from textbooks that stop at `synchronized` and toy producer-consumer examples. Then they walk into a senior-level technical round and get destroyed by questions about lock-free queues, memory visibility guarantees, or designing a thread-safe rate limiter under real load. The gap isn't talent. It's exposure. ---------------------------------------------------- 🧵 The 10-Day Interactive Concurrency Sprint This is a hands-on, browser-based Java sprint designed for working Senior SDEs who already write production code but need to close the concurrency gap — fast. What makes it different: - Zero local setup — Every exercise runs in an isolated cloud workspace. Open a link. Write code. See threads race in real-time. - Production patterns, not academic theory — You'll build real primitives: non-blocking queues, custom thread pools, structured task scopes, and concurrent caches that actually handle contention. - Daily escalation — Day 1 starts at memory model fundamentals. Day 10 ends with you implementing a lock-free data structure from scratch. - Self-paced, no scheduling required — All content is async. No calendar coordination. Work through it on your own schedule. This isn't a course that teaches you what a mutex is. It's one that makes you dangerous enough to design systems that don't need one.