Kotlin Skill

Language Context

This project uses Kotlin 1.9.25 targeting JVM 17. All source files are .kt located under src/main/java/ (legacy layout — do not move them).

Key Kotlin Conventions for This Project

Null Safety

• Use ?.let { } for null-safe chaining — this is the dominant pattern
• lateinit var for @Value-injected Spring properties
• Optional<Host?> return types are used in some repository/service methods — unwrap with .orElse(null)
• Never use !! — prefer safe calls or early returns

Data Classes vs Regular Classes

• JPA entities are regular classes (not data class) — required by Hibernate
• DTOs like PasswordDto, TimeLogDto, GenericResponse are regular classes with var/val
• Use object for constants (AppConstants), enums for type-safe constants