Kotlin Basics – A Beginner’s Guide to Kotlin Programming

Introduction

Kotlin is a modern, expressive, and powerful programming language designed for Android, web, backend, and multiplatform development. Officially supported by Google, Kotlin is now the preferred language for Android app development and is widely used by companies like Google, Netflix, Pinterest, and Uber.

In this guide, you will learn:
✅ What Kotlin is and why it’s useful
✅ How to set up a Kotlin development environment
✅ How to write your first Kotlin program
✅ Basic syntax and structure of Kotlin code

By the end, you’ll have a strong foundation to start writing Kotlin programs with confidence.

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1. What is Kotlin?

Kotlin is a statically typed, cross-platform programming language developed by JetBrains in 2011. It is fully interoperable with Java, meaning you can use both Kotlin and Java code in the same project.

Why Kotlin?

Kotlin was designed to overcome the limitations of Java while improving developer productivity. Here’s why developers prefer Kotlin:

✅ Key Features of Kotlin

Feature	Description
Concise	Reduces boilerplate code compared to Java
Safe	Eliminates common errors like null pointer exceptions
Interoperable	Works seamlessly with Java code
Expressive	More readable and modern syntax
Multiplatform	Can be used for Android, web, backend, and iOS

Example: Kotlin vs. Java Comparison
Consider the following Java code:

public class Main {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}

Now, look at the Kotlin equivalent:

fun main() {
    println("Hello, World!")
}

✅ Kotlin is shorter, cleaner, and more readable!

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2. Setting Up Your Kotlin Development Environment

Before you start writing Kotlin code, you need a development environment. Here are your options:

Option 1: Using IntelliJ IDEA (Recommended)

IntelliJ IDEA, created by JetBrains, provides built-in support for Kotlin.

Installing IntelliJ IDEA & Kotlin

1️⃣ Download IntelliJ IDEA (Community Edition is free).
2️⃣ Open IntelliJ IDEA and select “New Project”.
3️⃣ Choose “Kotlin” > “Kotlin/JVM” and click “Next”.
4️⃣ Select a project name and location. Click “Finish”.

Your Kotlin project is ready!

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Option 2: Using Android Studio (For Android Development)

If you’re building Android apps, Android Studio comes with Kotlin support.
1️⃣ Download Android Studio.
2️⃣ Install the Kotlin plugin (if not already installed).
3️⃣ Create a new Android Project and select Kotlin as the language.

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Option 3: Using Kotlin Playground (Online Compiler)

If you don’t want to install anything, use Kotlin Playground to run Kotlin code in your browser:
🔗 Kotlin Playground

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3. Writing Your First Kotlin Program

Hello, World! Program in Kotlin

Let’s write a simple Kotlin program that prints "Hello, World!" to the console.

fun main() {
    println("Hello, World!")
}

Explanation:

• fun main() {} → Defines the main function, which is the entry point of a Kotlin program.
• println("Hello, World!") → Prints “Hello, World!” to the console.

Output:

Hello, World!

✅ Kotlin doesn’t require a class like Java, making it much cleaner!

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4. Kotlin Basic Syntax

Now, let’s understand some fundamental syntax rules in Kotlin.

A. Variables in Kotlin (val vs. var)

Kotlin has two types of variables:

val language = "Kotlin"  // Immutable (Cannot change)
var age = 25            // Mutable (Can change)
age = 26                // Allowed

✅ Use val (immutable) when you don’t need to change the value.
✅ Use var (mutable) when you need to update the value.

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B. Kotlin Data Types

Kotlin supports various data types:

val name: String = "Alice"
val age: Int = 25
val pi: Double = 3.14
val isKotlinFun: Boolean = true

✅ Kotlin automatically infers types, so specifying them is optional.

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C. Kotlin Functions

Functions help organize code.

fun greet(name: String): String {
    return "Hello, $name!"
}

println(greet("Alice"))

✅ Functions improve code reusability and readability!

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D. Kotlin Conditional Statements

Use if and when for decision-making:

val num = 10
if (num > 0) {
    println("Positive")
} else {
    println("Negative")
}

Using when:

val day = 3
val dayName = when (day) {
    1 -> "Monday"
    2 -> "Tuesday"
    3 -> "Wednesday"
    else -> "Invalid day"
}
println(dayName)

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5. Why Kotlin is the Future?

✔ Google’s Preferred Language for Android Development
✔ Adopted by Big Tech Companies (Netflix, Pinterest, Uber)
✔ Fast-growing developer community
✔ Used for Backend (Spring Boot, Ktor), Web, and Multiplatform apps

Now that you’ve learned the basics, you’re ready to dive deeper! 🚀

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Conclusion

In this post, you learned:
✅ What Kotlin is and why it’s powerful
✅ How to set up Kotlin and run your first program
✅ The fundamental syntax, variables, and functions

🎯 Next Post: Kotlin Variables and Data Types – Understanding val, var, and Null Safety