🧭 Migration Checklist — From Java (OOP) to Go 🦫

📘 Table of Contents

1. 📐 Design & Architecture

  • Prefer composition over inheritance — embed structs instead of subclassing.

  • Design small, focused interfaces that describe behavior, not objects.

  • Organize code by domain or feature, not by technical layer.

  • Avoid creating “God objects” — structs should have clear, limited responsibility.

  • Keep packages cohesive; avoid circular dependencies.

2. 🔧 Structs & Interfaces

  • Use structs for data and behavior when needed, not as “classes.”

  • Add methods to structs only when they logically belong there.

  • Define interfaces at the consumer side, not the producer side.

  • Don’t write getters/setters unless they add real logic or validation.

  • Use factory functions (NewX()) instead of constructors.

3. 🧠 Mindset & Philosophy

  • Embrace simplicity and explicitness — Go avoids “magic.”

  • Don’t over-engineer abstractions — solve real problems first.

  • Follow idiomatic Go: clear, readable, minimal.

  • Prefer composition, interfaces, and functions over deep hierarchies.

  • Read standard library code — it’s the best example of Go idioms.

4. 🧵 Memory & Pointers

  • Use pointers when modifying a struct or avoiding large copies.

  • Use values for small, immutable, or short-lived data.

  • Remember that maps and slices are already reference types.

5. ⚡ Error Handling

  • Handle errors explicitly: if err != nil { … }.

  • Wrap errors with context using fmt.Errorf("msg: %w", err).

  • Avoid panic for control flow; use it only for truly exceptional cases.

  • Remember: no exceptions, no try/catch — explicit handling wins.

6. 🧪 Testing & Mocking

  • Use interfaces for mocking only when necessary.

  • Keep tests simple and clear — Go favors integration tests.

  • Avoid test frameworks with heavy magic; use testing and testify.

7. 🔄 Concurrency Tips

  • Learn goroutines — they’re cheap and safe for concurrent work.

  • Use channels for communication, not shared mutable state.

  • Prefer context cancellation for graceful shutdowns.

  • Avoid overusing sync primitives like Mutex; prefer message passing.

8. 📦 Project Organization

  • Use cmd/ for main entry points.

  • Use internal/ for private code.

  • Use pkg/ for reusable libraries (if needed).

  • Keep main.go minimal — wire dependencies explicitly.

  • Store configs in .env or a config package.