Object-oriented design fundamentals, SOLID principles, and the classic Gang-of-Four design patterns — explained through refactors of real anti-patterns, not just definitions, with the follow-up questions interviewers actually ask.
The object-oriented refresher and all five SOLID principles, each taught through a violation-then-refactor, before moving on to named design patterns.
Singleton, Factory, Abstract Factory, and Builder — the patterns that control how objects get created, each taught through the specific problem it solves.
Adapter, Facade, Decorator, Composite, Proxy, Bridge, and Flyweight — patterns that compose classes and objects into larger structures without the combinatorial mess of inheritance.
