Best Practices You Should Already Be Using

1. Naming: ClassName, methodName, CONSTANT_NAME, variableName. Names that tell a story beat comments.
2. One responsibility per class. If you can't describe what a class does in one sentence, split it.
3. Immutability where possible — final fields, no setters, defensive copies for collections.
4. Handle null deliberately. Use Optional<T> for return values that can be empty; use Objects.requireNonNull(x, "x") to validate.
5. Resources — open inside try-with-resources so files/sockets/JDBC close automatically.
6. Exceptions — never swallow them silently. Catch only what you can handle. Use checked exceptions sparingly; prefer unchecked + clear messages.
7. Equals + hashCode — override them together whenever you put your objects in a HashMap/HashSet.
8. Concurrency — favour java.util.concurrent primitives over raw Thread/synchronized when you can.
9. Tests — write small JUnit tests as you go. They double as living documentation.

Mini-Project Ideas

Pick one and ship it — the easiest way to consolidate everything in this course.

Where to next?

• Spring Boot — REST APIs, dependency injection. • Maven / Gradle — build tooling. • JUnit 5 + Mockito — testing. • Concurrency — Executors, CompletableFuture. • Design patterns — Singleton, Factory, Strategy, Observer.

Finish the qualifying quiz to unlock your certificate. Aim for 70% or higher. Good luck! 🎓