🚀Boosting Kotlin Performance: Essential Knowledge in 15 Best Practices!

Android App Performance

Introduction

Although Kotlin is an advanced language for writing clean and efficient code, it is essential to follow specific strategies to enhance performance. In this guide, you will find 15 best practices that can be employed to optimize the performance of your Kotlin applications.

Let’s Start

1. ‘val’ Usage

Using ‘val’ (immutable) ensures that a variable is assigned only once and cannot be modified thereafter. This contributes to code readability and reliability. Additionally, the compiler can optimize immutable values more effectively.

// Bad
var x = 5

// Good
val x = 5

2.Avoid Creating Unnecessary Objects

Creating objects can increase memory usage and lead to unnecessary computational overhead. It is advisable to refrain from creating unnecessary objects, especially within loops or heavily utilized areas.

// Bad
val list = ArrayList<String>()

// Good
val list = mutableListOf<String>()

3.Use ‘When’ Instead of Long if-else Chains

Replacing long if-else chains with ‘when’ makes your code cleaner, more readable, and easier to maintain. Moreover, the ‘when’ expression is one of Kotlin’s powerful and flexible features, often resulting in better code when used effectively.

// Bad
fun describeNumber(number: Int): String {
    if (number == 1) {
        return "One"
    } else if (number == 2) {
        return "Two"
    } else if (number == 3) {
        return "Three"
    } else {
        return "Other"
    }
}

// Good
fun describeNumber(number: Int): String {
    return when (number) {
        1 -> "One"
        2 -> "Two"
        3 -> "Three"
        else -> "Other"
    }
}

4.Reduce Code Nesting

Excessively nested code blocks diminish code readability and introduce unnecessary complexity. Reducing nested blocks enhances code clarity and opens up opportunities for potential performance improvements.

// Bad
fun processUserData(user: User?) {
    user?.let {
        it.address?.let {
            // code block
        }
    }
}

// Good
fun processUserData(user: User?) {
    user?.address?.let {
        // code block
    }
}

5.Optimize Collection Operations

Properly utilizing collection operations can enhance performance by avoiding unnecessary loops and object creations. Using asSequence() directs operations to laziness, processing elements only when needed.

// Bad
val doubledNumbers = numbers.map { it * 2 }.filter { it > 10 }

// Good
val doubledNumbers = numbers.asSequence().map { it * 2 }.filter { it > 10 }.toList()

6.Lazy Initialization

Utilizing ‘by lazy’ allows a property to be initialized only when its value is first accessed. This can reduce application startup time and optimize memory usage.

// Bad
val expensiveResource = ExpensiveResource()

// Good
val expensiveResource by lazy { ExpensiveResource() }

7.Avoid Unnecessary Null Checks

Using null-check operators and nullable types prevents NullPointerExceptions, ensuring code safety. However, performing unnecessary null checks can lead to performance overhead.

// Bad
if (name != null) {
    // code block
}

// Good
name?.let {
    // code block
}

8.Use the Safe Cast Operator

The as? operator safely performs type casting, returning null if the cast fails. This prevents ClassCastException, making the code more robust.

// Bad
val result: String = someObject as String

// Good
val result: String? = someObject as? String

9.Optimize String Concatenation

String concatenation operations, especially within loops, can cause performance issues. Utilize more efficient methods like “$” interpolation or StringBuilder to optimize this process.

// Bad
val fullName = firstName + " " + lastName

// Good
val fullName = "$firstName $lastName"

10. Use apply for Object Initialization

In Kotlin, the apply function is employed for creating objects and performing specific operations on them. apply is designed to make the object initialization process more effective and readable. Here are some advantages of using the apply function:

// Bad
val person = Person()
person.name = "John"
person.age = 30
person.city = "New York"

// Good
val person = Person().apply {
    name = "John"
    age = 30
    city = "New York"
}

11. Use Coroutines in Asynchronous Programming

Coroutines simplify asynchronous programming and manage threads more efficiently. Choosing coroutines over callbacks or traditional thread management can make your code more effective.

// Bad
fun fetchData(callback: (result: String) -> Unit) {
    // code block
    callback("Result")
}

// Good
suspend fun fetchData(): String {
    // code block
    return "Result"
}

12. Optimize Database Access

Efficient query usage and selecting performance-oriented libraries for database access can enhance your application’s database performance.

// Bad
val result = database.query("SELECT * FROM table")

// Good
val result = userDao.getAllUsers()

13. Cache Used Values

Caching values can improve performance by avoiding repeated computations. In this example, previously calculated values are stored in a cache, reducing the need for recomputation for the same input.

// Bad
fun calculateExpensiveOperation(input: Int): Int {
    // expensive calculation
}

// Good
val cache = mutableMapOf<Int, Int>()

fun calculateExpensiveOperation(input: Int): Int {
    if (input !in cache) {
        cache[input] = // expensive calculation
    }
    return cache[input]!!
}

14. Effectively Manage Resources

Managing resources (files, network connections, etc.) effectively prevents memory leaks and performance issues. The lateinit keyword indicates that a variable will be initialized later, providing a check before usage.

// Bad
var file: File? = null

// Good
lateinit var file: File

// To check before using the file
if (!::file.isInitialized) {
    file = File("file_path")
}

15.Use Up-to-Date Libraries and Tools

Continuous improvements and updates are made in Kotlin language and used libraries. These updates may include performance enhancements. Using up-to-date libraries and tools ensures your code benefits from the latest performance advantages.

Summary

While Kotlin is a powerful language for writing clean and efficient code, it is important to employ specific strategies to enhance performance and make the code more readable. The 15 Kotlin performance optimization tips shared in this guide aim to guide developers in optimizing and making their code more effective.

• Readability and Maintenance Ease: Suggestions such as using val Kotlin Standard Library functions, and the when expression contribute to making your code more readable and easier to maintain.
• Performance Enhancement Strategies: Recommendations like lazy initialization, optimizing regular expressions, and improving database access provide effective strategies for boosting application performance.
• Best Practices Specific to Kotlin: Using Kotlin-specific tools like the apply function is crucial for optimizing object initialization and configuration, making the code more concise.

In conclusion, Kotlin developers can utilize these guidelines to enhance performance and make their code more effective and readable. However, each application is unique, and performance improvements should be based on profiling and measurement of the code. These recommendations should be used as a guide to improve the code writing process and focus on fundamental principles.

References

Boosting Kotlin Performance: 10 Essential Tips for Efficient Code

Kotlin Performance Tuning: 20 Best Practices You Should Know

Optimizing Kotlin: Best Practices for High-Performing Apps