Master LLD, Concurrency & Microservices, then nail the interview
Low-level design & design patterns, Java concurrency & multithreading, and event-driven microservices — full story-driven chapters to learn it from scratch, plus a real interview question bank to prove you know it.
What's inside
Learn From Scratch
Story-driven chapters that build every concept from first principles — SOLID principles, design patterns, thread safety, event-driven pipelines — with real Java code throughout.
Real Interview Questions
A curated question bank drawn straight from the material, with an AI tutor that builds a complete zero-to-expert answer for every question, on demand.
Diagrams, Chat & Flashcards
Generate a visual diagram for any topic or question, ask the AI tutor a follow-up, and review with spaced-repetition flashcards that bring weak spots back sooner.
Categories
Low-Level Design & Design Patterns
SOLID principles, all 23 Gang-of-Four design patterns, and a capstone system-design walkthrough -- learned from real, motivating problems, not memorized definitions.
Java Concurrency & Multithreading
Threads, synchronization, the java.util.concurrent toolkit, and modern Java concurrency (virtual threads, structured concurrency) -- built from a race condition happening on purpose, not memorized API lists.
Event-Driven Microservices
CQRS, Event Sourcing, and the Saga pattern, built end to end with Axon Framework and Spring Boot -- learned by assembling one event-driven banking system, piece by piece, not by memorizing pattern names.
Frequently Asked Questions
What are the most commonly asked low-level design interview questions?
Interviewers typically ask you to design a system (a parking lot, a rate limiter, an elevator, a cache) from scratch — testing whether you know SOLID principles, can pick the right design pattern, and can defend your class structure. All covered here with dedicated learning chapters and an interview question bank.
Should I learn design patterns before Java concurrency?
Either order works, but design patterns build intuition for structuring code cleanly, which makes concurrent code — where structure mistakes turn into race conditions and deadlocks — much easier to reason about. This course covers both tracks independently so you can start with whichever you're weaker on.
What is the difference between concurrency and multithreading in Java?
Concurrency is the broader idea of multiple tasks making progress over the same time window. Multithreading is one specific way to achieve it in Java, using the Thread class and the java.util.concurrent package — locks, executors, atomic variables, and the higher-level utilities built on top of them.