Need for enforcing JSR-305 in Kotlin

• By default any sort of Java reference is a platform type in Kotlin.
• Since Java does not allow for expressing type-safety, the null-checks for Java references are relaxed in Kotlin
• This affects Kotlin’s sought-after null-safety feature
• However, the null-checks can be made strict  by adding the -Xjsr305 compiler flag with the strict options

// build.gradle.kts
 
tasks.withType<KotlinCompile> {
  kotlinOptions {
    freeCompilerArgs += "-Xjsr305=strict"
  }
}

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Refs §

1. https://kotlinlang.org/docs/java-interop.html#null-safety-and-platform-types
2. https://spring.io/guides/tutorials/spring-boot-kotlin