Scala

Scalable Language. It interops seamlessly with Java.

When to Use

• Big Data processing (Spark)
• High-concurrency systems (Akka)
• Functional programming on the JVM
• Complex domains

Quick Start

object Hello extends App {
  println("Hello, World!")

  val list = List(1, 2, 3)
  val doubled = list.map(_ * 2)
  println(doubled)
}

Core Concepts

Functional & OOP

Classes and traits mixed with higher-order functions and immutability.

Immutability

Default preference for immutable data structures (val vs var).

Pattern Matching

Powerful switch-like construct.

x match {
  case 1 => "one"
  case "two" => 2
  case _ => "other"
}

Case Classes

Immutable value objects with built-in equals, hashCode, and pattern matching support.

Best Practices

Do:

• Prefer immutability (val)
• Use Option instead of null
• Leverage the type system
• Use scalafmt

Don't:

• Write "Java in Scala"
• Overuse implicit conversions (can be confusing)
• Use return keyword (expression-oriented)

References

• Scala Documentation