After updating the Kotlin language, a NoClassDefFoundError error appeared, how to fix it?

Question

IntelliJ IDEA

Kotlin: [Internal Error] java.lang.NoClassDefFoundError: Could not initialize class com.intellij.pom.java.LanguageLevel

Maybe someone faced such a problem, after updating to the latest release, there was such a problem

Answer 1

Try: File -> Invalidate caches / Restart...

Answer 2

IntelliJ IDEA told me that I need to install the Kotlin plugin. I installed it and the
error disappeared

fun main (args: Array<String>){
    println("Hello, World!")
}

Answer 3

If it's still relevant - I created the project not like in the book, but through Gradle -> Kotlin / JVM. Then I waited until everything was downloaded to me, and then I created the main.kt file (I think the name can be any) along the path src -> main -> kotlin and already created an entry point there (which is fun main())