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Difference between Kotlin and JAVA

Updated Dec 10, 2019

If you are an Android application developer for the mobile, you are bound to come across Java. But due to the advent of technology, many new languages are coming into the limelight. One of the most popular languages that have entered the app development scenario is Kotlin.

Kotlin might challenge the dominance of Java in the Android world. In 2018, Google announced that is it is the second official language for Android development. Since then the language has been in demand both in the programming community.

To find out which language has an edge over the other, you need to look at the technicalities. In this article, we will perform a head to head comparison of Java and Kotlin.

JAVA Vs Kotlin


It is easier to write a program using lesser lines of code with Kotlin. This is not so easy in Java. Developers often complain about the amount of boilerplate code in Java. According to JetBrains, Kotlin is able to reduce the number of code lines by almost 40 %.

For example, you can write less code while using the findViewByIds in Android. Through Kotlin, you can import a reference to the View for your Activity file. You can then work on that View like it were a part of the Activity. So, you have to write fewer lines of code.

Community support

Kotlin is still in the early stages of development and use. Therefore, the language has a small community that is increasing day by day. At present, around 34,000 repositories are available in GitHub for Kotlin. The language holds around 26 % of the market share of the android applications currently.

Java is way ahead than Kotlin in terms of community support. Launched nearly decades ago, there are more than 800,000 repositories of Java on GitHub available. It has a massive community on GitHub and Stack Overflow. So, chances are that you will definitely find the solution to your problem online.

Android Studio support

Java is lagging behind when it comes to Android Studio 3 support. The latest version of Java, SE 10 does not work well with Android Studio 3. But, Java 7 and 8 are supported by the software platform. Therefore, the developers are not able to use the latest features of Java along with Android Studio.

So, naturally, they are shifting towards Kotlin. As Android Studio is based on IntelliJ IDEA, it is easily compatible with Kotlin.

Checked exceptions

Kotlin has no checked exceptions for catching and declaring exceptions. Thus, you can avoid the try/ catch blocks of code that create increase the coding time.

Java has checked exceptions for catching errors. Developers do not like them because the APIs incorrectly specify them. The code may get complicated using checked exceptions.

Kotlin vs Java - Head to Head Comparison

Basis of comparison



Null values

No variable types cannot be assigned null values. Assigning null value will throw a compile-time error.  

Null values can be assigned to any variable. But NullPointerExceptions are tricky that arise when you might try to access an object having null value

Data classes

Classes with keyword data will create a class to hold some data. This will instruct the compiler to create a constructor and methods for obtaining data from the user

For creating a class to hold data, you have to create a constructor, setter and getter methods and required functions manually.

Extension functions

Extend functions help you to enhance the functionality of a class.

There are no extend functions in Java. To improve the functionality of a class you need to create an entirely new class. You have to inherit the parent class.


Smart casts perform implicit casting using the ischeck keyword.

You have to cast the variables according to the function or class by checking them

Functional programming

This is a combination of functional and procedural programming that consists of concepts like operator overloading and higher-order functions.

There is no support for functional programming until Java 8.

What is Kotlin?

Kotlin is a programming language developed by the coders from JetBrains. It is a statically typed language that is also open source. It is based on the Java Virtual Machine (JVM). You can compile Kotlin to Javascript or native. By this, you can write code that can be executed on iOS.

Moreover, using Kotlin’s Multiplatform framework, you can create a common codebase. You can use this to run the code on all platforms such as JVM, Android, native and Javascript. Developers will only have to use one Kotlin IDE (Integrated Development Environment). This enables them to create applications for all other platforms.

It has a special LLMV compiler technology. This allows users to compile the code and execute it easily on multiple platforms like Mac, Windows and Linux.

Since its recognition by Google, the language has gained serious momentum. Many Google developers have already switched to Kotlin from Java. According to them, Kotlin
allows creating applications faster with lesser coding time. This has enhanced their productivity.

At present, major organisations such as Twitter, Pinterest, Evernote and Trello are opting for Kotlin for their Android applications.

Advantages of Kotlin

The benefits of using Kotlin are as follows:

  • Making a switch from Java to Kotlin is easy. Developers only have to install a Kotlin plugin and add it to their build files.
  • It currently has huge traction in Android application development. However, it is also beneficial for use in backend projects such as Spring 5.
  • It is compatible with all of the frameworks designed for Java.
  • You can write Kotlin modules and run them along with your Java code without any hassle.
  • Switching to Kotlin from Java does not cost anything.

What is Java?

Developed by Sun Microsystems, Java is one of the most powerful programming languages of the world. It is being used since 1995 and is popular for its object-oriented facilities. It was created by James Gosling and was the initial choice for developing Android applications. This is because Android was written in Java.

Before Android development, Java was widely used for creating applets. These were small programs that executed on web browsers. Static web pages could be converted into dynamic pages facilitating user interactivity.

Java has three components. They are:

JVM (Java Virtual Machine) – This offers a runtime environment for executing Java applications. This converts the Java bytecode into instructions that the operating system can understand. A JVM instance is created when a Java command is written.

JRE (Java Runtime Environment) – This executes the Java bytecode. It provides all the libraries and class libraries and files the JVM needs during runtime.

JDK (Java Development Kit) – This includes the JRE and has other tools required for application development. It is used to compile, document and package Java programs.

Advantages of Java

The benefits of using Java are:

  • Java is platform-independent. This is due to its bytecode that can be executed on any platform having the JVM installed.
  • It is flexible. You can run Java code on a web browser or through the JVM.
  • The language supports multithreading. So, the Java programs can execute multiple tasks at a time.
  • It is easy to compile and debug.

Why use Kotlin for Android?

Developers are choosing Kotlin over Java as it reduces the amount of code needed for developing applications. Less code means fewer errors to handle that eventually enhances productivity.

Features like smart casts, data classes and extension functions make the development process easier. Moreover, it is interoperable with Java. Thus, all the Java tools and frameworks are compatible with Kotlin.

Kotlin has support for Android Studio 3. So, you can utilise all the newest features of Android Studio without much effort. Just installing a Kotlin plug-in will help you integrate projects seamlessly.

Kotlin’s powerful compiler is boosting its presence in the Android development community. The compiler detects errors during compilation and performs a lot of checks. These reduce the number of bugs in the project.

Furthermore, its built-in support for null safety is great for hassle-free coding in Android.


If you are a developer looking to code less and get the job done, Kotlin will be great for you. Having many inbuilt features, it has already gathered a developer base of more than 1 million. You can easily integrate your Java code with Kotlin to while making applications.

Kotlin may be the new cool kid on the block. But, when it comes to community support and packages, Java is the king. So, if you are a beginner looking to experiment, Kotlin is a good choice. But, if you want to stick to old school android development, Java is good to go.