What is Kotlin all about??

What:

Kotlin is a statically typed programming language developed by JetBrains(who has introduced Intellij and Webstorm to us) that targets the JVM, Android, JavaScript and Native( In Experimental mode).

Why:

Because kotlin is:

• concise
• Can cut 40% lines of code (Rough estimates)
• Type safe
• Support for Non-Nullable types (to reduce NPE's)
• Smart casting
• Higher order functions
• Extension functions
• Coroutines (Async Programming without using RxJava nor Scary creepy threads)
• Kotlin Scripting
• Good Support with Frameworks like (Spring, Vert.x etc)
• Interoperability with java
• Lambdas with receivers provide the ability to write expressive code as well as facilitating creation of DSL.
• Kotlin is free to use (OpenSource)
• Kotlin is Object oriented and Functional Programming or Mix

Really Amazing!!! Isnt it??? But what if your project is already built on Java????

Dont Worry :-) Kotlin provides the interoperability to support kotlin in your java project. In other words, I can say class by class you can convert Java to Kotlin. You can use Java to Kotlin converter to convert your code with slight modifications if needed any.

Java to Kotlin Converter

Where can I use Kotlin:

Kotlin can be used for any kind of development, be it server-side, client-side web or Android. With Kotlin/Native currently in the works, support for other platforms such as embedded systems, macOS and iOS is coming. People are using Kotlin for mobile and server-side applications, client-side with JavaScript or JavaFX, and data science, just to name a few possibilities. -- From Kotilin Offical doc: https://kotlinlang.org/docs/reference/faq.html

Why it became popular now a days ?

Because Google officially announced Kotlin will be the First-class language for Android Source: https://www.theverge.com/2017/5/17/15654988/google-jet-brains-kotlin-programming-language-android-development-io-2017

Inspiration for Kotlin?

Actually Kotlin is inspired from existing languages like Java, C#, Scala, Groovy. I feel Kotlin is easier to learn and onboard faster.

How to Install and Run a HelloWorld?

Installation: Install first Java JDK (Kotlin currently in Java8) (https://discuss.kotlinlang.org/t/kotlin-support-for-java-9-and-java-10/8054/11) https://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html

With IDE: (Intellij)

Kotlin installation is very easy if you are using any IDE like Intellij because Kotlin already bundled with it. You can download http://www.jetbrains.com/idea/download/index.html Community Edition(Free for community) or Ultimate (Paid one though). Please find the below Gif for more info.

Without IDE:

If you wanted to use Kotlin without Intellij then you need to download Kotlin compiler from https://github.com/JetBrains/kotlin/releases/tag/v1.3.41 (Latest release is 1.3.41) Manual Install Unzip the standalone compiler into a directory and optionally add the bin directory to the system path. The bin directory contains the scripts needed to compile and run Kotlin on Windows, OS X and Linux. HomeBrew: $ brew update $ brew install kotlin

HelloWorld Program:

fun main(args: Array<String>) {
    println("Hello, World!")
}

Execute:

$ kotlinc hello.kt -include-runtime -d hello.jar 
    -d option to include the runtime in the resultant jar to run as a jar

REPL: (Read-Eval-Print loop)

After Successful installation of Kotlinc, go to terminal and type Kotlinc and write println("Hello World") and type :quit to exit

References: -- From Kotilin Offical doc: https://kotlinlang.org/docs/reference/faq.html
https://www.theverge.com/2017/5/17/15654988/google-jet-brains-kotlin-programming-language-android-development-io-2017