Kotlin vs Java – Which is better for Android app development?

Kotlin vs Java - Android App Development

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.

Which mobile applications are developed using Kotlin?

Popular apps like Pinterest, Evernote, Postmates, Coursera, Trello, Uber are developed in Kotlin language.

top apps developed using Kotlin

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 give answers to common questions of Android developers, we decided to compare Android Java vs Kotlin features.

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

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Difference between Kotlin vs Java

Kotlin vs Java

Kotlin vs Java

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

Sr. no.FeaturesKotlinJava
1Extension functionsAvailable in Kotlin. Extensions are useful as they allow developers to
add methods to classes without making changes to their source code.
In Java, we 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 keyword with variables, methods, blocks, and nested class.
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 expression like Kotlin.
5CoroutinesIn Kotlin, coroutines are concurrency design pattern.
It can be used to simplify code on Android that performs asynchronously.
Coroutines were added to Kotlin in 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. 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 Kotlin compiler to track conditions inside if expression.
If the compiler finds a variable that is not null of type nullable, the compiler allows accessing the variable.
No, 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-LoadingYes, 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.
9No checked exceptionsKotlin removed exceptions entirely in order to minimize verbosity and improve type-safety.In Java, the checked exceptions feature is a problem as it causes empty catch blocks.
10Operator overloadingYes, Kotlin allows users to provide a way to invoke functions.
It allows us to do an arithmetic operation, equality checks, or comparison on 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 + operator for concatenation and addition. Another Java type can’t reuse this operator.

Why Kotlin Over Java?

Why Kotlin over Java for Java Virtual Machine? Kotlin is a great fit for developing server-side applications, enabling users to write concise code than Java, allowing them to solve the same problems with fewer lines of code. It enhances code maintainability and readability that means engineers can write, read, and change code more efficiently.

In short, Kotlin can be used for anything where Java is used today, including server, client, web, and Android development. 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


  1. Is Kotlin better than Java?

     When it comes to comparing both the languages and selecting the one which is better, then go for Kotlin because Kotlin’s documentation, Kotlin code is implemented in a lot 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. Whereas 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. Still, Java is the faster 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 of the Android code is still written in Java. After understanding the basics of Java, you can go with Kotlin code. In case, if 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.

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This page was last edited on December 28th, 2020, at 7:14.

Author Bio

Amit Patolia

Amit Patolia

Designation: Android Team Lead

Amit Patolia is an Android Team Lead at Space-O Technologies. He has over 7 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.


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