Kotlin Introduction

What is kotlin?

Kotlin is a statically typed, object-oriented language and general-purpose programming language

It runs on JVM. It’s compatible with Java that means java code can be used in kotlin

Why Use Kotlin?

• kotlin is open source programming language.
• Easy to learn. it has basic syntax. If you know java
• it’s compatible with Java
• it’s multiplatform so you can run program on any machine which supports JVM.
• it is safe than java

Features of Kotlin

• Null safety: kotlin eliminate the NullPointerException by providing null safety features . In Kotlin every variable is Non nullable.
• Concise : It reduces writting the extra code.
• Compilation Time: It has better performance and fast compilation time
• Interoperable: you can use java code from kotlin and kotlin code from java.
• Statically typed: that means every variable and expression will be checked on compile time.
• Smart Cast: It explicitly typecasts the immutable values  and inserts the value in its safe cast automatically.

if try to access without smart cast it gives compile time error

fun main(args: Array){
    var str: String? = "Coding Friction"          
        print(str.length)       // compile time error
    }
}

fun main(args: Array){
    var str: String? = "Coding Friction"
    if(str!= null) {               // smart cast
        print(str.length) 
    }
     print(str?.length) //  can't get length if str is null 
}

Applications of Kotlin language:

• Android  applications
• Web development
• Server side applications And more.