IntelliJ Idea or any other IDE that supports Kotlin syntax
JVM (as Kotlin is a JVM based language)
Introduction
JetBrains started project Kotlin in 2011. Kotlin is designed to be complied as fast as Java and having the features of Scala. Scala, as JetBrain points out, has a high compilation time. Kotlin has saveral variations that target the JVM (Kotlin/JVM), JavaScript (Kotlin/JS), and native code (Kotlin/Native). Kotlin is interoperable with Java. That means that we can have projects with both Kotlin and Java code.
New Project – Intellij
File -> New -> Project -> Kotlin (JVM | IDEA)
Your First Code – HelloWorld
In the src directory, right click and click on new Kotlin file, let’s call it helloWorld.kt
Write “main”, and IntelliJ will autocomplete the main function. This main is the start point of our Kotlin application. Function/method is represented by fun.
val variable1: Int = 22 // variable1 is variable that is of Int type
val variable2 = 44 // variable2 is inferred as of type Int
Nullable values
Variables in Kotlin by default does not support null. Question mark after variable type says that the variable supports null. Following example will show the usage.
val can not be reassignedCan not call with null value
funmain() {
val variable1 =10
println(variable1)
//variable1 = 20 //Illegal Expression because val can not be reassigned
var variable2 =20
println(variable2)
variable2 =30
println(variable2)
//printNum(null) // Illegal Expression because variable a is not nullable
printNum(20)
printNullNum(null)
}
funprintNum(a:Int){
println(a)
}
// Notice the question mark after Int which represents that vara is nullable
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