I have a Kotlin source file, but I want to translate it to Java.
How can I convert Kotlin to Java source?
You can compile Kotlin to bytecode, then use a Java disassembler.
The decompiling may be done inside InteliJ Idea, or using FernFlower https://github.com/fesh0r/fernflower (thanks @Jire)
There was no automated tool as I checked a couple months ago (and no plans for one AFAIK)