Why use Kotlin over Java for Android Development

Write once, run anywhere – the alluring catchphrase of Java still seems relevant. Since Sun Microsystems unveiled Java, it has remained the most popular programming language in use. Object-oriented and class-based, Java stood its ground even when the development space became saturated with a plethora of new languages. However, with time, programming languages do get phased out once newer and better platforms take over.

And then came Kotlin. The search for a tenable Java alternative reached fruition with Kotlin, a statically-typed programming language running on the Java Virtual Machine (JVM). Essentially, Kotlin stripped Java of its complexities and came up with a refined alternative that is as versatile as its predecessor.

The Czech software company JetBrains unveiled Project Kotlin in 2011 with the objective of coming up with a better alternative to Java. They looked to Scala, another Java alternative with support for functional programming, but were taken aback by its slow compilation times.

Kotlin Goes Public

In 2016, JetBrains launched Kotlin v1.0, its official stable release to the public. Kotlin immediately gained traction among the Android development community. They lauded its refined framework and faster compilation times, complete with added tool support, as a significant advantage over Java. Things gained momentum when Google announced Kotlin as a first class language for developing Android apps at the I/O 2017.

What followed was an outburst of mainstream apps all written fully or partially with Kotlin. Kotlin had everything that developers couldn’t find in Java or any of its alternatives like, JRuby or Groovy. It is concise and 100 percent interoperable with Java. Added to that, Kotlin came with extensive compatibility with Android Studio in which IntelliJ IDEA, JetBrains’ own Java IDE serve as the backbone.

With interest in Kotlin skyrocketing, global adoption rates point to a widespread disruption.  From freelance developers to software development houses, the adoption of Kotlin has increased manyfold.  In the Stack Overflow Developer Survey Results of 2018, Kotlin is just behind Rust as the most loved programming languages. In the near future, Kotlin could become the de facto standard in Android development.

Kotlin’s Development Philosophy Strikes a Balance

Andrey Breslav, Kotlin’s lead language designer at JetBrains highlighted that the goal of Kotlin is to serve as a general-purpose language, which is concise, adaptable and fully interoperable with Java. By giving these extended set of functionalities, JetBrains intends to push the developer to migrate into Kotlin. Plain old Java has numerous flaws and the developers at JetBrains couldn’t conceive things as they wanted. For them, greater interoperability and productivity in the language is the need of the hour to quickly compile and execute code.

When working with Kotlin, we could easily pinpoint its structural similarities with its parent language, Java. The brains behind Kotlin did not just want to create a new language, but one which is in all ways a “better language” than Java. Platforms like Scala, although they offered extensive feature list and functionality, failed when it comes to build times and tool support. Kotlin managed to tick all the right boxes and struck a balance on how an ideal Java alternative should be.

Kotlin borrows some elements from Scala to bring out a more upgraded version. In fact, one could find that Kotlin does contain certain instances from other programming languages as well. Pascal, an early procedural and imperative programming language remained fairly influential in the development of Kotlin. Certain elements of it, like parameter lists and variable declarations with the data type following the name of the variable could be found in Kotlin too.

Bringing Full-Scale Interoperability with Java

What distinguishes Kotlin from other languages is its full interoperability with Java and the Android runtime. It is easier to call existing Java codes from Kotlin and Kotlin codes from Java. Developers could use all the Java frameworks to build highly responsive and feature-rich apps. Both the platforms, Kotlin and Java, identify each of their classes as their own, which enables seamless interchange and compatibility. This interoperability with Java could be demonstrated with a few lines of Java code as listed below:


class MainActivity : AppCompatActivity() {

override fun onCreate(savedInstanceState: Bundle?) {



    // accessing "getSum"  method from a java class

    val result = SumHelper.getSum(1, 2)




public class SumHelper

public static int getSum(int val1, int val2){
       return val1+val2;

Fig 1. Kotlin – Java Interoperability

This extensive interoperability of Kotlin with Java owes it to the fact that JetBrains worked on all the limitations of Java and sought to bring out something more refined. Together, the team worked on a new version that is different but still has Java as its backbone. Besides, Kotlin fully supports Java 6 and 7, the current versions used by Android developers.

Java Lacks Key Elements that Current Developers Need

Java has been around for more than two decades. Developers still continue to build great apps using its highly versatile and robust framework. Like every language, Java too has its limitations chiefly because it is old. Even though numerous updates were released over the years, they failed to address some essential problems associated with coding using Java.

When it comes to Android development, Java lacks support for key elements like lambdas, streams, method references, etc. Null Pointer Exception continues to be a fundamental flaw of Java, particularly in the way it handles them. Null references in code often referred as the Billion Dollar Mistake is the key reason why several apps written in Java still undergo occasional crashes.

Moreover, Java is verbose and takes a lot of code to get even a simple program up and running. The APIs involved in Java get rather complicated as the developer is forced to go through multiple steps, which take more time. Kotlin, on the other hand, requires lesser coding than Java by reducing both redundant and boilerplate code, making development a whole lot faster.

A Class Declaration in Java

public final class PersonJava {

private final String name;

private final int age;

private final String email;

private final long phone;

public PersonJava(String name, int age, String email, long phone) {

this.name = name;

this.age = age;

this.email = email;

this.phone = phone;


public String getName() {
return name;


public int getAge() {
return age;


public String getEmail() {
return email;


public long getPhone() {
return phone;



In Kotlin

data class PersonJava(val name: String, val age: Int, val email: String, val phone: Long)

Fig 2. Side by Side Comparison of Kotlin and Java Code

Lesser code means developers can write a program in lesser time and the code has greater readability combined with fewer chances of bugs or manual coding errors. Memory leaks are also a frequent problem with Java due to the way it implements anonymous inner classes and nested classes.

Kotlin Edges out over Java in Conciseness

With Google’s official endorsement, Kotlin has become the most commonly used language for Android development. The simplicity and robustness of Kotlin means both proficient and novice developers can write and debug applications with ease. Generally, Kotlin requires fewer steps or ceremonies when writing code, which simplifies the process altogether. Compared to Java, Kotlin has:

  • More concise class declarations because of primary constructors and properties
  • Robust type interface eliminates the need for repeating the same types again
  • Function parameters with default values mostly do away with delegating overloads
  • Availability of top-level functions substitute static utility classes

Being more concise than Java, Kotlin edges it out when it comes to ease of coding. It takes a redefined approach to programming to untangle several complicated workflows that developers face when using Java.

Meanwhile, Kotlin’s less verbose coding decreases the time taken to code and enhances the readability while also reducing the chances for any errors or bugs. Writing lesser code means developers can reduce the number of boilerplate codes while improving their productivity and avoiding tediousness.

Get Started with Android Development using Kotlin
With in-depth and hands-on expertise in Android development, Fingent’s dedicated team has helped enterprise organizations develop android applications using Kotlin’s extensive features.  Talk to our experts today!      Get A Free Quote! 

Kotlin is Nothing but an Improvised Version of Java

A notable benefit of Kotlin over Java is that it does not sway from being completely independent of the latter. In fact, Kotlin is an improvised form of Java, with all its limitations sorted out. Kotlin still relies on Java libraries but refines them all together to improve their functionality.

In the existing Java ecosystem, Kotlin manages to integrate each of its elements like the Java libraries, APIs and frameworks. In fact, Kotlin incorporates Java’s procedural and functional programming aspect at the right balance. Besides, its lightweight framework combined with modern features make it a refined version of Java that is in every way better than the original.

Android Development Gets Swift and Efficient with Kotlin

Kotlin aims at being pragmatic and productive at the same time all the while serving itself as a general purpose language fully compatible with Java. Owing to its compactness, Kotlin has proved itself a workhorse among the Android development community. It steers clear of all the limitations of Java with its full interoperability with the existing ecosystems of libraries and code. Here are a few reasons why Kotlin remains the ideal platform for Android development currently.

Developer Friendly:

Novice developers can easily learn and adapt Kotlin owing to its simplicity. It takes less time to learn to code with Kotlin due to its uncomplicated learning curve. Developers already proficient in Java would appreciate the familiarity of its coding process and streamlined approach to programming. Meanwhile, the availability of existing Java libraries, frameworks and lesser coding, amps up the speed of coding, allowing developers to conceive applications faster than before.

Excellent IDE Support:

IntelliJ IDEA, JetBrains’ own platform serves as the base for Android Studio and thus offers extensive IDE support to Kotlin allowing developers to seamlessly build apps. This ready integration with the IntelliJ IDEA framework enables access to its wide range of productivity tools. Configuring Kotlin plugin could be undertaken within minutes in Android Studio. Besides, every single process of coding in Kotlin from writing, navigation, debugging and unit testing happens effortlessly with the improved support offered through the IDE.

Enhanced Versatility:

Kotlin was designed to address some of the fundamental flaws in Java and it did well. Integrated into its framework is a built-in null checking feature that helps avoid frequent errors. Kotlin’s compiler also includes a feature that automatically corrects mistakes in the code simultaneously while it is being written in the console. These rich features negate several issues in Android development giving developers a clean and versatile platform to work with. Besides, it allows developers to streamline the production process through its features like search and auto-completion of code.

Open source:

JetBrains announced open source status under Apache 2 for Kotlin in 2012. The Java to Kotlin converter tool can seamlessly convert an existing Java project into Kotlin to save on time and work. Besides, it is completely free to use for any developer wishing to expand their skill set or get acquainted with its refined framework.

Summing Up

Every new language introduced into programming has the potential to disrupt it. Developers, when faced with limitations while working on their existing language readily adopt a new language that mitigates these issues. And Kotlin proved to be just that with Java. Its swiftness and concise nature proved instrumental in its widespread adoption among the Android development community.

For them, Kotlin seemed a better Java and its great interoperable support combined with expressive nature meant they could code just like they did with Java but in a fast and efficient manner. That does not mean that it will completely phase out the former. Java will still be around as a versatile language for years.

In times to come, newer versions of Kotlin gets released, which would be more developer friendly and complete with added features and support. More apps will utilize Kotlin to develop Android apps and there will come a point where it will ultimately substitute Java. Moreover, the steep adoption rates signal an increasing prominence of Kotlin for Android development in the near future.

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    About the Author

    Girish R

    Girish R, Programmer for 17 yrs, Blogger at Techathlon.com, LifeHacker, DIYer. He loves to write about technology, Open source & gadgets. He currently leads the mobile app development team at Fingent.

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