All 23 patterns — and the problem each one actually solves.
What you covered
💡 The Bottom Line, one more time
Creational patterns (Singleton, Factory Method, Abstract Factory, Builder, Prototype) control how objects get created, so the rest of your code doesn't have to know or care about messy construction details. Structural patterns (Adapter, Bridge, Composite, Decorator, Facade, Flyweight, Proxy) control how objects and classes compose into larger, still-flexible structures. Behavioral patterns (Chain of Responsibility, Command, Interpreter, Iterator, Mediator, Memento, Observer, State, Strategy, Template Method, Visitor) control how objects communicate and share responsibility, so no single class has to do or know everything. None of these patterns are goals in themselves — each one is a named answer to a specific, recurring problem. The skill worth keeping isn't memorizing the 23 names; it's recognizing the problem shape when you see it in real code, and reaching for the pattern that actually fits instead of forcing one in where it doesn't belong.
What's next
This track covered the classic Gang-of-Four catalog. From here, the natural next steps are:
- Revisit SOLID Design Principles — most of these patterns are really SOLID principles given a name and a concrete shape; seeing the connection both ways deepens both.
- Refactoring to patterns — the skill of noticing an existing, working codebase quietly needs one of these patterns, and introducing it safely in small steps.
- Architectural patterns — MVC, layered architecture, and event-driven architecture apply these same ideas of separation and delegation at the scale of a whole application, not just a few classes.
These will show up as new tracks on learn.appcafe.in as they're published — no need to go looking elsewhere.