Kotlin vs Java – Which is Better for Your Android App Development Project?

If you are a newbie Android developer and a little bit confused between Java and Kotlin, or if you don’t exactly know the differences between Kotlin vs Java for Android development, then this post is for you.

Herein we have compared both the programming languages based on their features and functionalities, so you can have a look at the comparison and decide which language has advanced features for Android development.


Java exists in the market for the past 23 years and most of the Android applications are developed using Java. So you know about Java, Android Studio, and Android API.

But, have you heard about Kotlin, the new programming language for Android? Java alternative? Yes, Kotlin is Google’s official new programming language for writing Android apps.

What is the Difference Between Kotlin Vs Java?

Here is the comparison table for Android Kotlin and Java performance that you can check to get detailed information about both languages.

Sr. no.
1Extension FunctionsThe extension function is available in Kotlin. Android extensions are useful as they allow developers to add methods to classes without making changes to their source code. Developers have the ability to extend a class with new functionality.Java developers need to create a new class to extend the functionality of the existing class, so from now users can use a newly created class everywhere to use the extended functionality.
2Null SafetyAvailable. Kotlin’s type of system has inbuilt null safety.Not available. In fact, NullPointerException is mainly responsible for the development errors of Android and Java.
3Static MembersIn Kotlin, we can use the companion object to create static members of the class.
An object declaration inside a class can be marked with the companion keyword.
Available in Java. It is used for memory management mainly. One can apply java static keywords with variables, methods, blocks, and nested classes.
4String TemplatesYes, there are two types of string literals in Kotlin such as escaped string and raw string.
Kotlin string template also supports expression.
Available in Java too, but it doesn’t support expressions like Kotlin.
5CoroutinesIn Kotlin, coroutines are concurrency design patterns. It can be used to simplify code on Android that performs asynchronously. Coroutines were added to Kotlin in the 1.3 version and they are based on established concepts from other languages.In Java, users have two different options, such as RxJava and Project Loom. RxJava is a library for composing asynchronous and event-based programs using observable sequences, and Project Loom supports a high-throughput, lightweight concurrency model in Java.
6Wildcard-typesNo, Kotlin doesn’t have any wildcard-types. But it has two other things, including declaration-site variance and type projections.Available in Java. The wildcard, in general, code means (?) that represents an unknown type.
It can be used in different situations.
7Smart CastsYes, this feature is available in Kotlin. It helps the Kotlin compiler to track conditions inside of the expression. If the compiler finds a variable that is not null of type nullable, the compiler allows accessing the variableNo, it is not available in Java. However, to know the types in Java, we can use something like an instance to check the type and then cast it to the right type.
8Lazy KeywordYes, it is available in Kotlin. It mainly decreased startup time that is useful when using Kotlin for app development.This feature is not available in Java.
9Operator OverloadingYes, Kotlin allows users to provide a way to invoke functions.
It allows us to do an arithmetic operation, equality checks, or compare whatever object we want through symbols like +, -, /, *, %, <, >.
In Java, operators are tied to particular Java types. For instance, String and numeric types in Java can make use of the + operator for concatenation and addition. Another Java type can’t reuse this operator.
10Blend of Functional and OOPKotlin is the blend of functional and object oriented programming.Java is based only on OOP (Object Oriented Programming).
11Language ScriptingKotlin offers language scripting capabilities to use the language straight into your Gradle build scripts.Java does not enable programmers to use language scripting capabilities.
12Lambda ExpressionLambda Expression is supported in Kotlin.The Lambda Expression is not supported in Java.

After knowing the major differences between Kotlin and Java, you must want to know about the top applications which are developed using Kotlin. Isn’t it? Check the next section.

Want to Create an Android App Using Kotlin?

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Best Applications Developed Using Kotlin

Tinder, Netflix, Airbnb, Pinterest, and Uber are some of the best android apps developed in the Kotlin programming language.

Applications developed using Kotlin

To know how Kotlin has helped these apps, let’s check the use case for each popular Kotlin-based mobile app along with the app category, revenue details, and links to download the apps.

LogoAppCategoryUse CasesRevenueDownload
TinderTinderSocial-networking AppKotlin has helped Tinder in its production environment for concise and clear code architecture.$1.4 billionAndroid iOS
NetflixNetflixVideo-streaming AppWith the use of 100% Kotlin, the Netflix Android app has rebuilt the current UI player.$24.9 billionAndroid iOS
AirbnbAirbnbTravel AppAirbnb uses Kotlin in the new Android product framework (MvRx) to offer travelers a better experience.$3.3 billionAndroid iOS
PinterestPinterestSocial-networking AppKotlin is the primary programming language for the Pinterest Android app. Migrating from Java to Kotlin has produced better outcomes, as it has reduced the time by building code with speed and efficiency.$442.6 million Android ios
UberUberOn-demand AppThis on-demand taxi service Android mobile app is built using Kotlin. It offers better internal tools and model management. Also, it offers error-free and faster performance.$14.1 billion Android ios

You might think which language is more useful and what are the unique features of Kotlin that are not available in Java, and why choose Kotlin for Android app projects rather than existing Java code. To answer the common questions of Android developers, we decided to compare the features of Android Java vs Kotlin.

So, to understand the benefits of moving from Java to Kotlin, you can go through the following infographic and identify on your own which language is more useful for your next project. To make it easy, we have also prepared an Android Java vs Kotlin infographic to give you a quick look into comparison.

Difference Between Kotlin and Java in Android

We have explained the differences between Kotlin and Java through this infographic image. We have compared both languages based on different features. Let’s check these features and get to know more about both programming languages.

Kotlin vs Java

Now you know the difference between Kotlin and Java, based on different features, but which one is a better option? Want to find out? Read the next section.

Kotlin vs Java: Which is Better?

Kotlin is a new programming language and statically typed programming language developed by JetBrains. It is a great fit for developing server-side applications, enabling users to write concise code than Java, allowing app developers to solve the same problems with fewer lines of code.

Kotlin enhances code maintainability and readability that means engineers can write, read, and change code more efficiently.

Looking at the benefits of Kotlin vs Java, developers can easily use Kotlin for anything where Java is used today, including server, client, web apps, and also for developing Android applications. Here are some of the other reasons to switch to Kotlin from Java:

  • Smarter and Safer Compiler
  • Less code
  • Easier to Maintain
  • Boost Productivity
  • Safer Code
  • Eliminating Null References
  • Data Classes
  • Type Inference

We have also mentioned some of the best advantages of using the Kotlin programming language. Check those benefits in the next section of this blog.

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Benefits of Kotlin

In this section, we will discuss the benefits of Kotlin in a detailed manner. Get to know how Kotlin helps to build highly efficient Android apps.

Kotlin Compile to JVM (Java Virtual Machine) Bytecode or JavaScript

Bytecode is the compiled format that is used for the Kotlin programs. It means, once the developer is programming the code and assembling it, it runs through a virtual machine and not through the computer’s processor.

The advantage of this method is that the developer can run the source code on any platform if it is compiled and run through the virtual machine. Moreover, if the Kotlin program is converted to bytecode, it becomes easy to transfer across a network and executed by JVM (Java Virtual Machine).

Kotlin is Capable to Use All Existing Java Frameworks and Libraries

The best advantage of using the Kotlin language is that you can still use all the existing Java libraries and frameworks. Moreover, the advanced frameworks as well that rely on annotation processing. The plus point of Kotlin is that a developer can easily integrate Kotlin with Maven, Gradle, and other build systems.

Easy to Convert from Java to Kotlin

With the help of a new feature integrated by JetBrains into IntelliJ, a developer can easily convert Java to Kotlin and save time. Also, you do not have to retype mundane code for Kotlin.

Null Safety of Kotlin

With Kotlin, you do not have to worry about NullPointerExceptions. The system of Kotlin will help us to avoid null pointer exceptions. If we compare Java vs Kotlin, the system of Kotlin easily refuses to compile code that assigns or returns null.

Do you still have some queries? Want to know whether Kotlin is better than Java or it is the same as Java, and many other questions that our reader frequently asked, then read our next section. Find all the questions one-by-one:

Frequently Asked Questions

  1. Is Kotlin better than Java?

    When it comes to comparing Kotlin vs Java and selecting the one which is better, then go for Kotlin because of Kotlin’s documentation; Kotlin code is implemented in a much easier form. In fact, we can say that Kotlin is much better than Java code in terms of security, compatibility, type inference, syntax, data classes, boilerplate code, and functional programming. At the same time, there are features similar on both Java and Kotlin, like lambda expressions, type system, and annotation processing.

  2. Is Kotlin the same as Java?

    No, Kotlin is not the same as Java in various points such as speed and performance. Java is a faster programming language than Kotlin. As one test revealed that Java has ~13% faster compilation speeds (with Gradle) than Kotlin (14.2 seconds vs 16.6 seconds) on average. However, the difference in speed is only for full builds.

  3. Should I learn Java before Kotlin?

    If you are completely new to the developer community and programming languages, then yes, you should first learn Java code because Android code is still written in Java. Java is an object-oriented programming language. After understanding the basics of Java, you can go with Kotlin code. In case you are an experienced developer, you can start with Kotlin’s course that teaches everything that you need to know about it.

  4. What is Kotlin good for?

     Kotlin is good for a lot of things like null safety, unchecked exceptions, property access, smart casts, and lazy loading. There are many other smart features of Kotlin that make it a good programming language.

  5. Is Kotlin good for web development?

    Yes, of course. Kotlin can be easily used for more than just Android. You can utilize Kotlin language for back-end systems in place of Java. In fact, you can use Kotlin for front-end development in place of JavaScript. In short, Kotlin is a full-stack solution that can be used on the server, in the web browser, and on mobile.


Herein we discussed and compared the major points of Java and Kotlin languages, explained why Kotlin over Java, and gave answers to some of the common questions related to Kotlin. We hope that this comparison helps you to understand the difference and decide which language is more preferable for you as an Android developer.

In any case, if you still have any confusion about whether to use Kotlin or Java for Android application development, what are the benefits of choosing Kotlin over Java, how to hire developers with expertise in Kotlin and Android Studio, get in touch with us through our contact us form or contact on given email address. One of our sales representatives will comprehend your app development project and suggest the right language to choose from.

Being a leading Android app development company, we have experienced in developing over 1500 Android apps. Refer to this portfolio section if you want to check how well our Android experts have built mobile apps for our clients.

Author Bio
Amit Patolia
Amit Patolia
Designation: Android Team Lead

Amit Patolia is an Android Team Lead at Space-O Technologies. He has over 9+ years of experience in Android app development. He has guided to develop over 100 Android apps with unique features and functionalities. He also has expertise in Kotlin-based apps.