kotlin-oo-fundamental

Design Kotlin object-oriented APIs for Java 8 interoperability by applying @Jvm* annotations, factory patterns, and overloads. This ensures clear contracts and ergonomic consumption from Java 8, reducing brittle inheritance and visibility issues.

Model closed hierarchies and value types in Kotlin using sealed and data classes. This approach enforces composition over inheritance, encapsulates mutable state cleanly, and establishes stable public contracts for domain-rich systems.

Manage visibility and module boundaries in a Kotlin library by enforcing strict visibility controls and versioning strategies. This preserves immutability and API hygiene, resulting in maintainable, testable, and evolvable public contracts.

Yes, you can use composition over inheritance for Kotlin backend library design through interface delegation. This testing-friendly dependency injection pattern encapsulates mutable state and avoids brittle inheritance hierarchies.

Kotlin APIs throw visibility or inheritance errors in Java due to default Kotlin behaviors lacking @Jvm* annotations. Apply overloads and factory patterns to ensure Java 8 ergonomics and clear module boundaries.