What is Scala?

Scala is a powerful programming language that combines:

• Object-oriented programming (OOP) → like Java

• Functional programming (FP) → like JavaScript, Python, Haskell

Its name means “Scalable Language” because it was designed to grow with your needs—from small scripts to large, high-performance systems.

Why Was Scala Created?

Scala was built to:

• Fix some complexities of Java

• Add modern features like immutability, pattern matching, lambda functions

• Support large systems (like LinkedIn, Twitter, Netflix)

It runs on the Java Virtual Machine (JVM), which means:

✔ You can use Java libraries
✔ It works anywhere Java works
✔ It is fast and scalable

What Makes Scala Special?

1. Runs on the JVM

You can mix Scala and Java in the same project.

2. Concise and expressive

Code is much shorter than Java.

3. Supports functional programming

Features like:

• higher-order functions

• immutability

• pattern matching

• map/filter/reduce

4. Very scalable

Used to build high-traffic platforms (e.g., Twitter).

Basic Syntax Examples

Hello World

object Hello {
  def main(args: Array[String]): Unit = {
    println("Hello, Scala!")
  }
}

Variables

val name = "Scala"      // immutable (recommended)
var age = 10            // mutable

Functions

def add(x: Int, y: Int): Int = {
  x + y
}

println(add(2, 3))

Functional Style

val numbers = List(1, 2, 3, 4)

val doubled = numbers.map(n => n * 2)

println(doubled)  // List(2, 4, 6, 8)

Pattern Matching (like switch but better)

val grade = 85

grade match {
  case g if g >= 90 => println("A")
  case g if g >= 80 => println("B")
  case _            => println("C or below")
}

Where Is Scala Used?

Big companies using Scala:

• LinkedIn

• Twitter (backend services)

• Netflix

• Airbnb

• Databricks

• Spotify

Best for:

• Large web services

• Distributed systems

• Data engineering

• Machine learning with Apache Spark (written in Scala)

Should You Learn Scala?

Learn Scala if you want to:

• Work with big data (Spark uses it)

• Build large, high-performance apps

• Use a mix of Java + modern functional programming

• Work at companies like Netflix, Twitter, or LinkedIn