Kotlin vs Java

For mobile app developers, Java is the go-to language for building Android applications. But, there are many new emerging languages all over the industry. This might challenge Java’s dominance in the Android world.

One of them is Kotlin, a new programming language. It has been already reported by Google as a “first-class” language supported on Android. Although, it is continually being developed and improved, Kotlin is already considered a mature ecosystem and its popularity is growing rapidly, particularly with the mobile development.

Here you get to know more detailed comparison- Kotlin vs Java. Let us see.

What is Kotlin?

Kotlin was designed by programmers from JetBrains to add some modern features to Java mobile development. It has certainly picked up momentum after being declared as an official programming language for Android at Google I/O in 2018. Google has also internally switched to using Kotlin rather than Java on Android. Kotlin is an open source, statically typed language based on the Java Virtual Machine (JVM), yet you can also compile it to JavaScript or native to build code that can run on iOS. Everything necessary is done with installing the Kotlin Plugin and allowing it to configure your project.

Pros of Kotlin-

  • Kotlin has a lot of traction in Android development, but it’s also used in backend projects such as Spring 5;
  • Kotlin is able to compile to almost every platform including Android, JVM, JavaScript, and native.  Using the Kotlin Multi Platform framework you can extract one common codebase that will target all of them at the same time;
  • Changing from Java to Kotlin is simple – just install the Kotlin plugin, add it to the Gradle build files, and click ‘Convert’;
  • It supports modern programming concepts like extension functions, higher-order functions, delegates, and more out-of-the-box to help devs build clean APIs;
  • Kotlin provides a built-in null safety support which is a lifesaver, particularly on Android, which is full of old Java-style APIs
  • It’s way is more concise and expressive than Java, which means less room for error;
  • You can write new modules in Kotlin and be sure they will work alongside the existing Java code; Kotlin is compatible with all Java libraries and frameworks, the JVM, and can integrate with the Gradle or Maven build systems;
  • Devs can take an advantage from a rapidly growing collection of open source projects on GitHub, many books, learning resources, and online courses;

Cons of Kotlin-

  • Rather steep learning curve when switching whole teams to Kotlin because of the language’s concise syntax.
  • More slow compilation speed than Java 
  • Has smaller developer community than Java. This means limited learning resources and trouble in discovering answers to questions; 
  • There are many more Kotlin developers available, anyway finding well experienced mentor for your team may require more effort;

Kotlin use cases-

  • Pinterest- It is a mobile app for the popular creative idea sharing social app; 
  • Trello- This is a visual tool for organizing work with customizable to-do lists.
  • CarLens-  This is a car recognition app powered by machine learning made by the Netguru R&D team for detecting cars and showing information about them. 

What is Java?

Java is the most preferred language among developers with regards to Android application development– essentially because Android itself used to be written in Java. Developed by Sun Microsystems (Now the property of Oracle), Java is an object oriented programming language that flaunts the title of the second most active language on GitHub. And its popularity seems to grow continuously.

Pros of Java-

  • Java is easy to learn and understand;
  • It is Flexible. You can run it in a browser window or a virtual machine. This comes in handy when you reuse code and update software;
  • Android depends on Java – the Android SDK contains numerous standard Java libraries;
  • Java has a huge open-source ecosystem, somewhat because of Google’s selection of the Java Virtual Machine (JVM) for Android;
  • Accelerated assembly within Gradle- we’re all grateful for it when assembling large projects;
  • Java applications are more compact and are simpler to be streamlined when better execution is required. Also, in contrast with Kotlin, Java applications will in general be lighter as Java is a more imperative language;

Cons of Java-

  • Java has limitations that cause problems with Android API design;
  • Java requires writing more code, which carries a higher risk of errors and bugs;
  • It is slower in comparison to many other languages. Also it requires a lot of memory.

Java use cases-

  • Android-oss – the official kickstarter.com Android app, a social platform for funding creative projects;
  • NewPipe- It is a lightweight video streaming app project for Android;
  • WordPress Engineering – The official WordPress App for Android. 

Why use Kotlin for Android?

What is the purpose of switching from Java to Kotlin? The primary argument may be the fact that Kotlin is intended to address Java’s issues. It implies that Kotlin provides numerous safety mechanisms available out-of-the-box while being more concise and expressive than Java simultaneously. Maybe that is the reason Kotlin is among the top five languages most preferred by developers, which represents % of developers who are developing with the technology or language and have expressed interest in continuing. 

Know the comparison of Kotlin with React native at- React native vs Kotlin.


While Kotlin has numerous advantages that Java doesn’t, despite everything, it has a few disadvantages. Many times transitioning to new language is not exciting for developers who have found the tools and strategies that work for them. You need to give some time for your team to get familiar with Kotlin. You also need to bear in mind that Java isn’t going anywhere and will stay essential for Android application development. But if you are thinking to adapt to new technology, can go with Kotlin.

Choosing the best technology for apps development is most important as it leads to the success. Here you have gone through detailed comparison of Kotlin vs Java. If you are still confused to choose the best one, consult with solace experts. Expert’s team is well proficient in new trends and technologies. We will be happy to help you.

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