Android programming language is easy to learn and also app development is cost-effective, which puts Android into great use. Developing Android applications is an excellent way of driving success for the business, but choosing the best programming language is always a critical decision for developers.

First, for many of us, the programming language that comes to mind is Java. But ever since Google announced Kotlin as an official language for Android development in 2017, android developers are in a dilemma to choose whether Kotlin or Java for development and started searching for various queries like:

  • Kotlin or Java for Android?
  • Which is better for Android Development java or kotlin?
  • What should an Android developer learn? Kotlin or Java?

And, the list goes on.

To resolve all your Kotlin vs Java issues for android development, we have decided to come up with this write-up.

Here, we'll discuss the significant differences between Kolin Vs Java and help you understand which programming language is a better choice for Android development.

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

Kotlin Vs Java: Overview

What is Java

Java is a native language used for Android development. It's an object-oriented language developed in 1995 and a favourite for many developers. Also, one of the well-known and easiest languages developed by Sun Microsystems, and later acquired by Oracle.

This programming language allows to create any program and supports any machine, regardless of architecture or platform. It's the second most active language on GitHub.

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What is Kotlin

Kotlin is an open-source and modern statically typed programming language used by over 60% Android developers today. It is developed by JetBrains to add some additional features to Java for mobile development. This programming language can be used for any type of development, be it - server-side, client-side or web. It's described as a general-purpose language and seen explosive growth in Android development since Google announced it has an official language of Android development.

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Coming to its importance, Kotlin strongly supports JVM in its Android ecosystem. And most importantly, Kotlin's language features and standard library functions enable succinct, effective code. 

Java Vs Kotlin: Pros

Pros of Java: 

The advantages of Java over Kotlin -

  • Java is multiplatform and easy to learn.
  • Android relies on Java - Android SDK includes many standard Java libraries.
  • Java has a large open-source community.
  • Java ensures faster development speed than Kotlin.
  • Its an object-oriented language and makes it easy to create modular applications and reuse the parts that contribute to the robustness
  • Compared to Kotlin, Java apps are more compact.
  • Accelerated assembly within Gradle

Pros of Kotlin:

The advantages of Koltin over Java -

  • Kotlin introduces improved syntax, concise expressions, and abstractions.
  • Kotlin application development is faster to compile and prevents apps from increasing size.
  • Code written in Kotlin is smaller compared to Java, which means fewer bugs.
  • Kotlin includes coroutines and interoperability with Javascript for web development.
  • Adopting Kotlin is free and switching from Java to Kotlin is simple, just by installing the Kotlin plugin and adding to the Gradle build files.
  • Interoperable with Java
  • Kotlin is safe against NullPointerException
  • Gained a lot of traction in android development, but can also be used in backend projects like Spring 5.
  • Developers can benefit from Anko library and over 2000 kotlin projects on Github.
  • Supports smart extensions to build APIs
  • Configures projects in Android Studio for auto-completion aids, and helps in detecting compile-time errors.
  • Fewer app crashes compared to Java.
  • Reduced project timelines

Kotlin Vs Java: Cons

Cons of Java:

  • Java syntax is a little complicated when compared with other languages.
  • Accessing new Java enhancements in mobile development is not an easy task.
  • Slower compared to other programming languages and require colossal memory space.
  • As a verbose language, test-driven development for Java requires more coding and increases a higher risk of errors or bugs.
  • Java causes problems with Android API design.

Cons of Kotlin:

  • Kotlin is younger than Java and has a small developer community which means limited resources to find solutions.
  • Switching teams to Kotlin is difficult due to the steep learning curve.
  • Compared to Java, slower compilation time.
  • Experienced Kotlin developers are still a rarity in the market, so finding a good mentor for your team is quite tricky.

Java Vs Kotlin: Major Applications

Major Applications built using Java:

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

Major Applications built using Kotlin:

  • Postmates - The on-demand food delivery app
  • Basecamp 3 - The project management app
  • Gradle - Open source build automation tool 
  • Evernote - The note and task organising app

Kotlin vs Java: Major Difference 

Following is the comparison table:

Parameter Kotlin  Java
Compilation Virtual machine Byte codes
Checked exceptions unavailable Available 
Code conciseness  Better than Java Can’t be labelled as concise
Null safety Available  Unavailable 
Lambda expression Comes as one of the prebuilt features Introduced in Java8
coroutines Available  Unavailable 
Extension functions Available  Unavailable 
In-variant array Available  Unavailable 
Non-private fields Unavailable  Available 
Static members Unavailable  Available 
Smart casts Available  Unavailable 
Wildcard types Unavailable  Available 
Singletons objects Unavailable  Available 
Inline functions Available  Unavailable 
Ternary operator Unavailable  Available 
Primitive types Variables of a primitive type are objects Variables of a primitive type aren’t objects
Community support  limited Very large 

Java vs Kotlin: Unique Features

What Java has that Kotlin doesn't:

Let's understand some of the significant features what Java supports that Kotlin doesn't:

  • Checked exceptions - Developers who like to build robust code with error recovery, Java's checked exceptions are still a highly coveted feature. Kotlin doesn't support checked exceptions.
  • Primitive types that are not classes - Byte code uses primitive types wherever needed, but they are not explicitly available. Char, double, float and byte are among the eight primitive types that serve the purpose of containing simple values of a kind. 
  • Static members - Java shares one instance of static member across all instances of a class. In comparison, kotlin has no provision for static members.
  • Wildcard types - This offers many benefits like field type, parameter, or local variable. While kotlin has no option to use it, Java allows developers to use it for extended functionality.
  • Ternary operator - In kotlin, there is no ternary operator. Java has a ternary operator similar to if statement for checking condition is true or false.

Now that you have understood what Java supports that Kotlin doesn’t. Next, we’ll see what features Kotlin supports that Java doesn’t.

What Kotlin has that Java doesn't: 

  • Null-safety -One of the most significant issues Java faced is NullPointer Exceptions, Kotlin solved these issues by making all types as non-nullable by default.
  • Lambda expressions and higher-order functions -A higher-order function is a function that uses functions as a parameter or returns a function. Kotlin functions are first-class, which means they can be stored in data structures and variables and operated in all the possible ways for other non-function values.As a static programming language, Kotlin makes use of a range of function types to represent functions and offers a set of specialised language constructs, called lambda expressions.

  • Extension functions -In Kotlin, you can extend a class with new functionality without inheriting it from other classes or design patterns by employing special declarations called extensions. To declare an extension function, you need to prefix its name with its receiver type, i.e. the type being extended.
  • Smart casts - Kotlin lets developers handle redundant casts automatically, without having the need of check type or cast inside a statement. Kotlin compiler performs "is-checks" for immutable values, and inserts cast when required automatically.
  • Separate interfaces for read-only and mutable collections- Compared to Java, Kotlin has separate interfaces to work with collections. Mutable collection interface manages data modifications, and plain collection interface takes data access.
  • String templates -In Kotlin, you can directly assign dynamic values to strings and print their statement using templates.
  • Type inference -The best thing about Kotlin is you don't need to define data type explicitly as Kotlin compiler automatically will do it through type inference.
  • Data classes -The main advantage of data classes in Kotlin is it generates a large amount of auto-generated code. A data class is a class that contains only the state and doesn't perform any operation.
  • Coroutines -Kotlin coroutines are design patterns used in Android development to simplify asynchronous code. They help you manage long-running and intensive tasks by suspending execution without blocking threads. 
  • Operator Overloading -Kotlin allows you to implement a predefined set of operators on their types using fixed symbolic representation and precedence.
  • Range expressions -In Kotlin, you can create ranges easily for any similar type using rangeTo() function.
  • Declaration-site variance and type projections -Compared to Java, Kotlin allows you to specify variance annotation on class declarations using a declaration-site variance.
  • Singletons -Kotlin uses singleton patterns as a replacement for static fields. Singletons ensure the creation of only one instance and thereby act as a single point of safety for thread safety. 

Now, that got a clear idea about what features these programming languages support. So, let's come to the central question of the blog, Kotin vs Java: Which is a better choice for Android development? The answer is kotlin, because, with features like less code, more declarative, and mixed-language database, Kotlin is more expressive than Java. It's a reliable, secure, and flexible language for both startups and enterprises. Further, being budget-friendly and improved efficiency, many top companies are preferring for Android developers having hands-on expertise on Kotlin. 

Now, let's know-how will be the future of Kolin.

The Future of Kotlin

The advantages of Kotlin are undeniably the future of development for Android developers. Many top organisations globally are adopting Kotlin as the official Android programming language. Kotlin is quickly proving itself to be a better programming language for Android application development and offering a plethora of great features with modern programming for developers. Google announcement about Kotlin programming language as a future of Android development, is definitive proof that the market for Kotlin will expand more in the coming days. 


With this, we have come to the end of this article where we compared Kotlin vs Java significant differences. We hope you will have a better understanding after reading this article. Considering the growing acceptance and recognition by major players in the Android space, future prospects suggest Kotlin seeming to take-over from Java. 

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