Running a simple hello world from the console after installing IntelliJ IDEA

Question

I have installed IntelliJ IDEA on my mac and wrote the simplest Kotlin program

fun main(args : Array<String>){

    println("Hello")
}

I can run it from the IDE environment. (It prints Hello of course)

My question: How can you run this from the console?

What I have done:

I tried to call

java simplekt.class

but I got Error: could not find or load main class simplekt.class

I tried java simplekt but then I got an exception in thread main java.lang.NoClassDefFoundError

I tried to use kotlin or kotlinc but the command was not found. (where is the compiler installed?)

In this resource they use kotlinc and they produce a jar file but IDEA only output a class file.

Not really sure how to proceed from here.

Answer 1

When you run your application from the IDE, in the Run window the very first line is the command that the IDE executes to start your program. In my case it's something like:

/Library/Java/JavaVirtualMachines/jdk1.8.0_181.jdk/Contents/Home/bin/java -Dfile.encoding=UTF-8 <a lot more omitted>

You can execute the same command in your terminal and that will execute the application. Reading that line will also (indirectly) tell you where the kotlinc command is installed, and in my case – using MacOS – it's at /Applications/IntelliJ\ IDEA.app/Contents/plugins/Kotlin/kotlinc/bin/kotlinc

However, you can always decide to entirely stop using the IDE and compile/run your program from the command line by following instructions here: https://kotlinlang.org/docs/tutorials/command-line.html