Kotlin Hello World Program

Kotlin is a statically-typed, general-purpose programming language. It is widely used to develop android applications.
Our Kotlin Tutorial includes all topics of Kotlin such as introduction, architecture, class, object, inheritance, interface, generics, delegation, functions, mixing Java and Kotlin, Java vs. Kotlin, etc.
Kotlin is a general-purpose, statically typed, and open-source programming language. It runs on JVM and can be used anywhere Java is used today. It can be used to develop Android apps, server-side apps and much more.
Kotlin was developed by JetBrains team. A project was started in 2010 to develop the language and officially, first released in February 2016. Kotlin was developed under the Apache 2.0 license.

Kotlin First Program Concept
Let's understand the concepts and keywords of Kotlin program 'Hello World.kt'.

fun main(args: Array) { println("Hello World!") }
1. The first line of program defines a function called main(). In Kotlin, function is a group of statements that performs a group of tasks. Functions start with a keyword fun followed by function name (main in this case).
The main () function takes an array of string (Array) as a parameter and returns Unit. Unit is used to indicate the function and does not return any value (void as in Java). Declaring Unit is an optional, we do not declare it explicitly.

fun main(args: Array): Unit {
//
}
The main() function is the entry point of the program, it is called first when Kotlin program starts execution.
2. The second line used to print a String "Hello World!". To print standard output we use wrapper println() over standard Java library functions (System.out.println()).
println("Hello World!")