Why Kotlin Beats Java for Mobile App Development

Why Kotlin Beats Java for Mobile App Development

Let’s say you have an Android application idea and you’ve ironed out most of the details but you’re unsure where to start. You’ll probably look to develop the app with Java. It makes sense - Java is the most popular programming language to develop Android applications. However, it comes with its fair share of issues. What other options do you have?

That’s where Kotlin comes in. Kotlin is a popular cross-platform, open-source programming language for the Java Virtual Machine (JVM). There are no restrictions with Kotlin. You can use your favorite languages in even less time resulting in fewer bugs.

Three Benefits of Kotlin

To start, Kotlin is a must for Android app development. In May 2019, Google announced Kotlin as the preferred language for Android app developers. JetBrains developed Kotlin with a goal of being able to compile just as quickly as Java, which allows a steady migration from Java to Kotlin.

Easy to Learn

Learning Kotlin is relatively easy for those already experienced with Java. You can start with the syntax then learn the paradigm of Kotlin as you code in the new syntax. You can even migrate current Java applications by adding new functionality in Kotlin, gradually rewriting older sections of Java code to Kotlin as developers have time. Kotlin and Java may co-exist within the same project.

Another bonus of Kotlin is it has a lot in common with Swift and iOS development language. This is where Java falls short as it is entirely different. Similarities include with Swift include data structure, declaring properties, and functions. Kotlin can be used as alternative to Swift too. Use the languages you know and utilize them in Kotlin for a cross-platform experience.

Time & Cost Savings

Kotlin saves you time. It allows you to share components across multiple platforms, preventing developers from having to build out each element twice in their native language. The source can be used for both back-end and front-end. Instead of writing different code for both Android and iOS, Kotlin allows app developers to share the same common logic for both platforms so it is easy to add another into the equation.


Kotlin is safer than Java because it prevents common errors in design which cause crashes and system failures. Because of Kotlin’s simplified framework, you can avoid bugs in production altogether. Kotlin detects bugs at compile time rather than at runtime. It performs a lot of checks in general which reduces errors in the code.

Syntax Differences

Syntax Differences

Java developers will notice that learning the new Kotlin syntax is simple. It is more concise and easier to read than Java. This leads to smaller, more understandable, and maintainable code bases. You are able to develop more reliable code and reduce bugs with fewer lines.

Null Safety

Null safety ensures no object references have a null or void value within the programming language. Kotlin will not compile code that results in a null pointer except those that are thrown. One of the biggest issues in many programming languages, such as Java, is null reference exceptions resulting from accessing a member of a null reference. Kotlin means to eliminate the risk of null references from code.

Data Classes

Kotlin has data classes that auto-generate the boilerplate code for equals, hashCode, toString, getters/settings, and more. With Kotlin’s data classes, it seeks to reduce the boilerplate code in the project.

Extension Functions

Kotlin allows you to extend the functionality and properties of existing classes without inheriting from them. If you have a third-party library that that you need to add functionality to, you can use Kotlin extensions to do this. You can call these functions and access these properties the same way you would any of the functions or properties that were originally part of the third-party library

Smart Casts

Kotlin compiler is very intelligent with casts. Many times, you don’t need to use explicit cast operators in Kotlin. Smart Casts can be used to save time and redundancy of an explicit cast like you would have to use in Java.

Functional Programming

Functional programming is more of a paradigm shift for the Java developer, but it is a real strength of Kotlin. Kotlin is a functional programming language. Kotlin consists of many methods, which include lambda expressions, lazy evaluation, operator overloading, and higher-order functions. This is also the foundation of the new Google Compose functional UI that will be released as part of Android Studio. It allows for nested UI elements to be coded into functions and abstracted out from the hardware level.

Co-Routines “lightweight-threads”

A very powerful feature of Kotlin is it removes the nightmare of callback nesting. Co-routine allows you to write asynchronous code that is perfectly readable and maintainable. One co-routine is not a single task but a sequence of subtasks that execute in a specific, guaranteed order. This is accomplished with Kotlin’s featured suspending function.

Mobile App Development Differences

Mobile App Development Differences

A major step with Kotlin is the ability to do cross-platform Kotlin Multiplatform (KMP) native development. KMP allows the developer to create completely native Android and iOS application with complete access to hardware and low-level SDK native functionality.

This is accomplished by writing the UI for Android in Kotlin in Android Studio, writing the UI for iOS in Swift in xCode, and a common module (library) containing business logic and network layer using Kotlin. The common module (library) is compiled into a jar for the Android Kotlin application and framework library for the Swift iOS application, which reduces time to market with iOS and Android platform applications. It also reduces redundant code that needs to be updated in multiple places as application needs change without losing access to the low-level hardware control and native libraries that are needed in so many of today's applications.


Being a more concise, Google-approved programming language, Kotlin is generally a preferred choice over Java for mobile app development. If you want to develop an app in Kotlin, Code Authority’s mobile app development team can work with you on a custom solution. Contact us today for a free consultation!