I have been playing around with Kotlin and I am liking it more and more. Its cleaner, less verbose, more functional adn comes with many advanced features. I will list down few with short examples

Kotlin vs Java Comparison

✅ Kotlin vs Java: A Feature-by-Feature Comparison

Kotlin is a modern, expressive programming language fully interoperable with Java and designed to overcome many of Java’s limitations. Here’s a detailed comparison of Kotlin’s key features versus Java, including advanced language capabilities.

🚀 1. Null Safety

Kotlin:

var name: String = "John"
name = null // Compile-time error

Java: All object references are nullable by default. Null safety relies on careful programming or external tools like Optional.

🧵 2. Concise Syntax

Kotlin:

val list = listOf("A", "B", "C")

Java:

List<String> list = Arrays.asList("A", "B", "C");

📦 3. Data Classes

Kotlin:

data class User(val name: String, val age: Int)

Java: Manual creation or use of tools like Lombok.

🔗 4. Extension Functions

Kotlin:

fun String.isEmail(): Boolean {
    return this.contains("@")
}

Java: No extension functions; you must use utility classes.

🧬 5. Coroutines for Async Programming

Kotlin:

suspend fun fetchData() = coroutineScope {
    // Async non-blocking work
}

Java: Uses CompletableFuture, which is more verbose and harder to manage.

📐 6. Smart Type Inference

val name = "Alice" // Inferred as String

Java: Type inference is limited and available only from Java 10+ using var.

🛠️ 7. Default and Named Arguments

Kotlin:

fun greet(name: String = "Guest") {
    println("Hello, $name!")
}

Java: Requires method overloading. Named arguments not supported.

🔒 8. Sealed Classes

Kotlin:

sealed class Result
class Success(val data: String) : Result()
class Error(val message: String) : Result()

Java: Supported only in Java 17+ using sealed keyword.

🔁 9. Functional Programming Support

Kotlin: Native support with lambdas, higher-order functions, etc.

Java: More verbose functional style introduced in Java 8.

🔄 10. Interoperability with Java

Kotlin: Can call Java code seamlessly and vice versa.

Java: Can interact with Kotlin (compiled to bytecode), but tooling is better from Kotlin to Java.

🔍 Additional Advanced Kotlin Features

🧾 Type Aliases

typealias UserMap = Map<String, List<User>>

⏱ Lazy Initialization

val config by lazy {
    loadConfiguration()
}

🧷 Delegated Properties

var name: String by Delegates.observable("<no name>") { _, old, new ->
    println("Changed from $old to $new")
}

🧩 Destructuring Declarations

val (name, age) = User("Alice", 25)

🛡 Safe Call (?.) and Elvis Operator (?:)

val length = name?.length ?: 0

📊 Summary Table

🧠 Conclusion

Kotlin offers a more modern, expressive, and safer syntax compared to Java, while maintaining complete interoperability. If you’re starting a new project—especially for Android or backend APIs—Kotlin is often the more productive and maintainable choice.