Java Vs Kotlin: A Head-to-Head Comparison for Mobile App Development

Java Vs Kotlin: A Head-to-Head Comparison for Mobile App Development

Quick Summary: In this article, we'll compare Java and Kotlin for mobile app development. We'll explore the similarities and differences between these two popular languages and help you decide which one is best for your next mobile app project.

In mobile app technologies, Java vs Kotlin is one of the most popular search terms.

When it comes to mobile app development, choosing the right programming language can make a big difference. Java has long been a popular choice for Android app development, while Kotlin has gained popularity in recent years as a more modern alternative. 

If you too are looking for a comparison of Java vs Kotlin frameworks, this blog is for you!

But first, let's begin with a small introduction to both these programming languages.

Key Differences Between Java and Kotlin
  • Kotlin is generally considered to be more concise than Java, with features such as type inference, lambda expressions, and extension functions that allow developers to write code more quickly and with fewer lines of code.
  • Kotlin has built-in null safety features that help to prevent null pointer exceptions, which are a common source of bugs in Java code.
  • Kotlin is designed to be fully interoperable with Java, meaning that Kotlin code can call Java code and vice versa. This makes it easy to migrate existing Java codebases to Kotlin or to use Kotlin modules within existing Java projects.

Introduction to Java

Java is a well-known language that came into existence 24 years ago (established in 1995 by James Gosling). It has a supreme position in the list of the most popular programming languages.

In fact, Java holds the highest usability record with a huge number of developers and systems. And most entrepreneurs prefer to hire Java developers to build tailored solutions for their businesses.

Why Java dominates the enterprise programming language realm.

Google is still utilizing Java for building Android mobile applications. Moreover, it is a primary driver of eCommerce engines including eBay and Amazon.

In addition to this, Java is a major contributor to the open-source community i.e. a wealth of resources and a lot of fun tools.

Introduction to Kotlin

Despite the undisputed reputation that Java holds, there was a need for a modern programming language. Kotlin fills this gap. Especially when Kotlin was declared the official language for Android apps.

Kotlin has actually turned the tables especially since Google officially announced Kotlin as the best language for Android app development at Google IO on 7 May 2019.

Difference Between Java and Kotlin

Simply put, the main difference between Java and Kotlin is that Java is an established language for Android development, while Kotlin is newer and offers modern features such as null safety and functional programming. Kotlin is more concise and expressive, designed to improve code quality and reduce errors while maintaining compatibility with Java.

Let’s have a complete overview of the difference between these two technologies via this blog post.

How Java Works

Java works on the principle of ‘Write Once & Run Everywhere’, which is platform-independent. The general-purpose computer programming language is concurrent, class-based, and object-oriented. The platform includes the execution of an engine, compiler, and a set of libraries. As a matter of fact, the language derives most of the syntax from C & C++.

How Kotlin Works

Kotlin is an open-source platform, based on JVM and can be compiled into JavaScript, Android, and Native and run on iOS. Fully compatible with Java stacks, it is a combination of object-oriented and functional programming features. This concise, safe & pragmatic language focuses on interoperability with Java code and can be used everywhere Java is used.

Java Vs Kotlin - Origin of the Programming Languages

Java: Java was developed by James Gosling and his colleagues at Sun Microsystems in 1995. Java is intended to be compiled to bytecode which is then run by JVM.

Kotlin: Kotlin was introduced by JetBrains in 2011 that is the originator of IntelliJ IDEA, PyCharm, and different top IDEs. The language has got its name from ‘Kotlin Island’ in St.Petersburg, Russia.

Java Vs Kotlin - Statistics

Java: Java is still the most popular programming language according to the TIOBE Index and is the second most searched language in PYPL (Popularity of Programming Language).

Kotlin: More than 50% of professional Android developers now use Kotlin to develop apps. And in the latest Stack Overflow developer survey, it ranks as the fourth-most loved programming language.

Java vs Kotlin Compilation

Java: Programs do not compile into executable files instead they compile into bytecodes. Then the JVM executes them at runtime. If you will use a Java compiler, the source code will compile into bytecode.

Kotlin: Like Java, Bytecode is the compiled format for Kotlin. The programming code which is once compiled and then run via a virtual machine instead of a processor is called a ‘bytecode’. This approach helps to run the code on any platform.


Despite the differences, both are 100% interoperable. You can call Kotlin code from Java and vice versa. So, it is possible to have Kotlin and Java classes side by side within the same project.

This flexibility helps the developers to swiftly switch between the two languages. For example, there are features you want to write in Kotlin and others you find easier to write in Java. As both compile to bytecode, the end-user will be unable to tell where Java code ends and Kotlin begins.

Java vs Kotlin

Java vs Kotlin

Java vs Kotlin - Comparison in Terms of Features

Features of Java

  • Platform Independent: Easily transferable after the compilation of Java program byte codes.
  • Secure: Authentication based on public-key encryption. It develops a virus and tamper-free system.
  • Robust: Tries to eliminate error-prone situations by focusing on compile-time error checking.
  • Multithreaded: Programs that can perform multi-tasks can be created simultaneously.
  • Dynamic: Java programs carry large run-time information and are more dynamic than C & C++.

Java vs Kotlin

Recommended Read: 20 Top Reasons to Choose Java for Backend Development!

Features of Kotlin

  • Highly Efficient: The language reduces the code length. The coding is 20% less than in Java. This improves quality and has become code efficient.
  • Extension Function: Kotlin developers can add extra features to the existing component without changing the major part of the code.
  • Interoperability: You can run Java codes on Kotlin and vice versa.
  • Low Adoption Cost: The open-source has a low cost of adoption so there is no need to invest money in a license
  • No Runtime Overhead: The library is small and doesn’t have garbage. It comprises focused extensions to the standard library.

IDE Support in Java vs Kotlin


  • NetBeans: Open-source integrated development environment accelerated after it became part of Apache. It supports all Java application types: Java SE, JavaFX, Web, and EJB.
  • Enide Studio 2014: Initially released as a standalone product for different operating systems, later it developed a Tool Suite for Node.js, JavaScript, and Java Development.
  • BlueJ: Running with the help of a JDK (Java Development Kit), its utilization is for educational purposes but also suitable for those who want to do small-scale development.
  • DrJava: DrJava is a very lightweight development environment to write programs in Java that are designed primarily for students. Also, Java developers can use it as a unit testing tool, source-level debugger, and pane for evaluating program text.


  • IntelliJ Idea: This IDE has a lot of versatility and stability. It has a number of tools for refactoring, software testing, and more. Furthermore, the code coverage analysis and integrated version control of the system which is very helpful. IntelliJ supports different languages like Java, Groovy, and Scala.
  • Android Studio: This is the only mobile development that offers fast tools for building apps on any type of Android device. This studio has had full support for Kotlin since May 2017.
  • Others include standalone compiler and eclipse.

Java Vs Kotlin - Online Tutorials

Although there are innumerable websites that give detailed insights about both languages but the most popular ones are:



Major Applications Built Using Java and Kotlin

Big brands are already using these top two programming languages. Here are a few examples of the applications that are extremely popular:


  • Google: The biggest search engine
  • NASA World Wind: Open-source virtual globe API
  • Uber: A transportation network company
  • Spotify: Digital music streaming service
  • Linkedln: Social network for professionals
  • Pinterest: Social image-sharing platform
  • Tripadvisor: Largest travel platform


  • Postmates: The on-demand food delivery app
  • Evernote: The note and task-organizing app
  • Basecamp 3: The project management app, easily accessible via browser or smartphone
  • Gradle: Open source build automation tool designed to develop any type of software

Java Vs Kotlin Comparison Table

Basis of Comparison




James Gosling and Mile Sheridan

Jet Brains and other contributors

Released Date



Latest Version

Java 17 LTS


Popular Language

Best according to Bootcamp Berkeley

Fourth according to Anaytics Insight


  • Platform Independent
  • Simple
  • Object Oriented
  • Secure
  • Robust
  • Multithread
  • Dynamic
  • Highly Efficient
  • Interoperability
  • Low-Adoption Cost
  • No Runtime Overhead
  • Extension Function

Online Sources

  • Java
  • Learnjavaonline
  • DZone
  • Stackify
  • Codeacademy
  • Kotlinlang
  • Programiz
  • Udemy

IDE Support

  • NetBeans
    Enide Studio 2014
  • BlueJ
  • Dr.Java
  • IntelliJ Idea
  • Android Studio

Major Applications

  • Google 
  • Nasa World Wind
  • Uber
  • Spotify
  • LinkedIn
  • Pinterest
  • Trip Advisor
  • Postmates
  • Evernote
  • Basecamp 3
  • Gradle

Checked Exceptions


No Provision Available

Conciseness of Code

Not Concise

Comparatively Less Code


More Complex

Manages Thread Better

Data Classes

Boilerpade Code is Written

Simple Way to Create Classes

Null Safety

Need to Assign a Null Value to a Variable

By Default Null Value

Extension Functions


Creating an Extension is easy

Java vs Kotlin: Which one to Choose for Android App development?

Java vs Kotlin: Which one to Choose for Android App development? Source - Google Images

Java is surviving for a very long time. Kotlin is basically a pragmatic enhancement of Java. Both programming languages resemble each other in various instance and offers great support for mobile app development.

Whether you hire mobile app developers for Java or Kotlin, your application will perform optimally. Where Kotlin has just made a fresh start, Java is like a best friend of enterprises, that has stood long and passed every test.

But as Google said, Kotlin is the future of Android mobile applications. It is a reliable, flexible, and secure language for both startups and enterprises. Not only it reduces errors but it also crashes at run-time making debugging reliable.

Furthermore, being budget-friendly and enhanced efficiency, it's best for companies to hire android app developers having hands-on expertise with Kotlin.

Are you planning to build your mobile app offshore? Want to build your team of Android app developers at your offshore office? We can help you set up your offshore development center in India.

Frequently Asked Question - Java Vs Kotlin

Which language is better for mobile app development: Java or Kotlin?
The answer to this question depends on a variety of factors, including the specific needs of your mobile app project and the skills and experience of your development team. Java is an established language with a large user base, while Kotlin offers more modern features and more concise syntax. Both languages are suitable for mobile app development, and the choice between them will depend on your specific needs and preferences.
Is Kotlin easier to learn than Java?
Kotlin is generally considered to be easier to learn than Java, thanks to its more concise syntax and modern features such as null safety and functional programming constructs. However, this may vary depending on the individual learner's background and experience.
Can Kotlin be used with existing Java code?
Yes, Kotlin is designed to be fully interoperable with Java, which means that Kotlin code can call Java code and vice versa. This makes it easy to migrate existing Java codebases to Kotlin or to use Kotlin modules within existing Java projects.
Does Kotlin offer better performance than Java?
Kotlin and Java both run on the Java Virtual Machine (JVM), which means that their performance is generally similar. However, Kotlin's more concise syntax and streamlined features may result in faster development times, which can be beneficial in certain situations.

Ashwani Sharma

Ashwani Sharma

A Technology Architect with a deep-rooted passion for System Design and development, he specializes in steering Digital Transformation initiatives for businesses. His expertise in AI/ML technologies empowers him to design intelligent systems that drive innovation and efficiency. Beyond his professional pursuits, he's a Proud Teacher, nurturing the next generation of tech enthusiasts and problem solvers.