Kotlin programs on the JVM commonly start at a top-level fun main() or fun main(args: Array<String>). No class wrapper is required for a simple file.
Kotlin · Lesson 1 · On the house
Hello, Kotlin
fun main, println, top-level entry. Lesson 1 is free — on the house.
Lessons · Kotlin · Lesson 1 of 10 · On the house
Hello, Kotlin
fun main, println, top-level entry.
println writes a line to standard output and adds a newline. print also exists but omits the trailing newline — idiomatic console demos use println.
Kotlin is case-sensitive: Println is not println. String literals need straight ASCII double quotes; curly “smart” quotes from a word processor break the compile.
Call syntax needs parentheses: println("hello"). Semicolons are optional and usually omitted.
Misses: writing public static void main (that is Java), using print when you meant a line break, or pasting curly quotes into the string.
hello
fun main() {
println("hello")
}Quiz
What is the usual top-level entry for a Kotlin JVM starter?
Quiz
Which call writes a line with a trailing newline?
Quiz
Is Kotlin case-sensitive?
Quiz
Which quotes belong in a Kotlin string literal?
Check
Match the still for: Hello, Kotlin.
Open-book: the answers are on this page. Pass every quiz and check (5) to mark the lesson done. This visit: 0/5.