Use JetBrains's Java annotations?

https://github.com/JetBrains/java-annotations/

Annotations like @Contract and @Range look useful, especially for those who uses IntelliJ IDEA.

[trustin]

@ikhoon Sounds good to me. We might want to introduce a new annotation that hides the direct reference to JetBrains’ @Nullable annotation, though:

@org.jetbrains.annotations.Nullable
...
public @interface NullableType {}

// in LoggingDecoratorBuilder:
... BiFunction<? super RequestContext, ? super Throwable, @NullableType ?> 

[ikhoon]

Kotlin understands checkerframework’s Nullable, however, Kotlin compiler does not produce an error message. It only helps remove platform-types. https://kotlinlang.org/docs/java-interop.html#notation-for-platform-types Unfortunately, JSR-305 is the only annotation that can produce a compilation level error message with -Xjsr305=strict. https://kotlinlang.org/docs/java-interop.html#compiler-configuration

For better inter-ops with Kotlin, JSR-305 seems the best option at the moment.