What is the Java equivalent of this code: ```inter...

# getting-started

[bodiam]

What is the Java equivalent of this code:

interface MyInterface<out T> {
    fun process(): T
}

I need to convert this interface to Java because of SAM conversion, but I'm failing a bit here.

[Eivind Nilsbakken]

interface MyInterface<T> {
    T process();
}

[bodiam]

Thanks, but are you super? I don't think that's matching the out parameter in my interface.

[bezrukov]

I think there is no equivalent code in java (in java there is no idiomatic and safe way to use Interface<T> as Interface<ParentT> - you need to perform explicit cast)

SAM conversion for kotlin interfaces will be supported in 1.4. Before it released you can write top-level fun
fun MyInterface(lambda): MyInterface = ...

[Eivind Nilsbakken]

Oh, yeah. ☝️

[bodiam]

Thanks Denis, but what do you mean with the last line?

[bodiam]

Right now I have:

return object: MyInterface<Any> {
   override fun process(): String = {
      // code here
   }
}

[bodiam]

but I'd like to make it a bit shorter.

[bezrukov]

inline fun <reified T> MyInterface(crossinline lambda: () -> T) = object : MyInterface<T> {
    override fun process(): T {
        return lambda()
    }
}

then just use it

val interface: MyInterface<String> = MyInterface { "Looks like it's SAM conversion" }
val anyInterface: MyInterface<Any> = interface

[bezrukov]

so you will write:

return MyInterface {
    // code here
}

[Ruckus]

Maybe a dumb question, but is there a reason you're not just using () -> T?

[bodiam]

I'm not sure what you mean with () -> T ?

[bodiam]

@bezrukov It worked really well btw, thanks for that!!