Is there a playground for playing with Java interoperability? Some kind of an online compiler that accepts both Java and Kotlin code at the same time..

If you use https://try.kotlinlang.org there’s a button that lets you paste Java code and converts it to Kotlin, but the editor doesn’t accept both languages at the same time, sorry.

yeah was looking for accepting both, but i did not now there is a converter! so cool, thanks!

you’re welcome, help yourself! Also IntelliJ is capable of converting code from Java to Kotlin. It’s a nice feature to get familiar with the language, but keep in mind the transformed code often won’t be very idiomatic for Kotlin.