dependency-injection.md

Spring: Dependency Injection Conventions

This document defines conventions for wiring Spring beans and configuration values.

Rule: Prefer constructor injection

Prefer constructor injection for Spring beans. Prefer val constructor parameters for injected collaborators and configuration values. Do not use field injection, setter injection, or mutable injected properties (for example @Value on a var) unless it is impossible to implement the component otherwise.

Example (preferred):

@Component
class SomeComponent(
    private val someService: SomeService,
    @Value("\${some.feature.enabled:false}")
    private val featureEnabled: Boolean,
)