Custom Null-Safety annotation is invalid in kotlin

Support
1

Stack Overflow link: https://stackoverflow.com/questions/63789139/custom-null-safety-annotation-is-invalid-in-kotlin

0

Infomation about custom Null-Safety annotation is from Kotlin official:

https://kotlinlang.org/docs/reference/java-interop.html

My java codes:

@TypeQualifierNickname
@Nonnull(when = When.ALWAYS)
@Retention(RetentionPolicy.RUNTIME)
public @interface NN {
}

@NN
public static <T> T notNull(@Nullable T nullable, String message) throws NullPointerException {
    return Objects.requireNonNull(nullable, message);
}

Error calling:

fun max(comparator: Comparator<in T>): T {
    val maxOrNull: T? = ...


    // IDEA error:
    // Type mismatch.
    // Required: T
    // Found: T?
    return Require.notNull(maxOrNull, "Collection is empty.")
}

But if I replace @NN to @org.jetbrains.annotations.NotNull , no error:

@org.jetbrains.annotations.NotNull
public static <T> T notNull(@Nullable T nullable, String message) throws NullPointerException {
    return Objects.requireNonNull(nullable, message);
}