Udemy – Low-Level Design in Java: OOP, SOLID & 11 Design Patterns

Stop freezing in LLD interviews. Start designing like a senior engineer. You’ve been asked “Design a Parking Lot” and didn’t know where to start. Or you opened a codebase and thought “who wrote this mess?” This course fixes both problems.

What you’ll learn:

• The 4 OOP pillars — Encapsulation, Abstraction, Inheritance, Polymorphism — with real Java code
• All 5 SOLID principles — spot violations instantly and fix them
• 11 design patterns (Singleton, Factory, Builder, Adapter, Decorator, Strategy, Observer, and more) — each taught 3 ways: the bad approach, a better try, the clean pattern
• A 6-step interview framework that works for ANY LLD question
• UML class diagrams — draw professional designs on a whiteboard in minutes
• 4 complete case studies: Parking Lot, Library, Elevator, Chess — requirements to working code
• Java power tools: Rich Enums, Records, Thread Safety, Atomic operations
• A full 45-minute mock interview simulation