Updated intellij messed up Kotlin with 'Check your module classpath for missing or conflicting dependencies'

Question

Lot's of frustration here. I decided to follow the pop-up prompting an intellij upgrade so it'd stop nagging me.

And now I get a compiler error on certain parts of the code:

Cannot access 'java.io.Serializable' which is a supertype of 'kotlin.String'. Check your module classpath for missing or conflicting dependencies

I can make a new kotlin project with only the following and run it:

fun main() {
    println("helloWorld")
}

But if I change it to the following it does not compile:

fun main() {
    println("hello" to "World")
}

$ java -version
java version "1.8.0_201"
Java(TM) SE Runtime Environment (build 1.8.0_201-b09)
Java HotSpot(TM) 64-Bit Server VM (build 25.201-b09, mixed mode)

I'm on windows. I find it very challenging to debug these kind of things. It feels very similar to this and this upvoted one

Answer 1

It was solved by downloading a jdk and applying it to the project:

Click the plus, select a vendor and download:

And then apply it to the project:

And rebuild.

Answer 2

I encountered some similar problem on IntelliJ and end up with clicking reload all maven projects button.