Kotlin Tutorial
Kotlin is a statically typed programming language that runs on the Java Virtual Machine, known as the Swift of the Android world, designed and open-sourced by JetBrains.
Kotlin can be compiled into Java bytecode, and can also be compiled into JavaScript, making it convenient to run on devices without a JVM.
At Google I/O 2017, Google announced that Kotlin became the official development language for Android.
My First Kotlin Program
Kotlin program files end with.ktsuch as: hello.kt, app.kt.
Simplest Version
package hello //Optional package header
fun main(args: Array<String>) { //Package-level visible function, accepting a string array as a parameter
println("Hello World!") //Semicolons can be omitted
}
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Object-Oriented
class Greeter(val name: String) {
fun greet() {
println("Hello, $name")
}
}
fun main(args: Array<String>) {
Greeter("World!").greet() //Creating an object does not require the new keyword
}
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Why Choose Kotlin?
- Concise: Greatly reduces the amount of boilerplate code.
- Safe: Avoids entire classes of errors such as null pointer exceptions.
- Interoperable: Fully leverages existing libraries for JVM, Android, and browsers.
- Tool-friendly: Can be built with any Java IDE or using the command line.