Kotlin Result Cannot Be Used As A Return Type. It means return to the position labeled as labelname with the value provided. Covariant type parameter with out modifier cant be used on public in positions and contravariant type parameter with in modifier cant be used on public out positions.
- - mathematical operators is also used to pass an array to a vararg parameter assignment operator. The error message you get tells you exactly that. It can be considered analogous to other wrapper classes such as Integer the wrapper for the primitive type int.
Unfortunately you cant replace your ResultHandler with Kotlins Result - because Result cant be used as a return type.
You correctly mentioned both ways to not return anything. Using this return control of the program is returned to the specified line in the program. The Void class as part of the javalang package acts as a reference to objects that wrap the Java primitive type void. So in Kotlin Void is something.