Error: Main method not found despite I have declared a main function

Question

I am new to kotlin and I am trying to use main function together with a class.

fun main() {
    var demo = Person("Hello", 10)

    println(demo)
}

private class Person (name: String, age: Int){
    var name: String
    var age: Int

    init {
        this.name = name
        this.age = age
    }
}

Although I have declared the main function, the compiler is still looking for the static main method in the class that I have defined, Person, and I got this error:

Error: Main method not found in class Person, please define the main method as:
   public static void main(String[] args)
or a JavaFX application class must extend javafx.application.Application

What have I missed?

Works fine for me: https://pl.kotl.in/MxpZrlMke Probably problem in the way you're running this code? — Михаил Нафталь, Aug 04 '21 at 12:44
I just do `kotlinc Person.kt` and then `java Person`. My version of `kotlinc` is `info: kotlinc-jvm 1.5.20 (JRE 16.0.1+9)` — John Winston, Aug 04 '21 at 14:48

score 0 · Accepted Answer · answered Aug 05 '21 at 11:05

java Person is the problem, you are specifically telling it to look for the static void main method there. Top-level functions from Person.kt will be compiled into a PersonKt class by default and so you should run java PersonKt.

Also, the unnamed package you get by not specifying any package is weird in some ways, so I would recommend adding a package declaration from the start (and running java your.package.PersonKt).

Error: Main method not found despite I have declared a main function

1 Answers1