Kotlin vs Scala: The Right JVM Language For App Developers

When you write and run a Java program, you are tapping the power of Java technologies. You express the program in source files written in the Java programming language, compile the source to Java class files, and run the class files on a Java virtual machine.

Updated 9 October 2023

Chandrapal Singh
Chandrapal Singh

Director at Appventurez

When you write and run a Java program, you are tapping the power of Java technologies. You express the program in source files written in the Java programming language, compile the source to Java class files, and run the class files on a Java virtual machine.

Together, the Java virtual machine and Java API form a “platform” for which all Java programs are compiled. In addition to being called the Java runtime system, the combination of the Java virtual machine and Java API is called the Java Platform.

At the heart of Java’s network orientation is the JVM, which supports all three prongs of Java’s network-oriented architecture: platform independence, security, and network mobility. However, one of the most discussed values related to programming languages also included Java vs Kotlin comparison.

JVM is an abstract computer. Its specification defines certain features every Java machine must have but leaves many choices to the designers of each implementation. For example, although all Java virtual machines must be able to execute Java bytecodes, they may use any technique to execute them.

JVM is a specification where the working of JVM programming languages is specified. But the implementation provider is independent to choose the algorithm. Its implementation has been provided by Sun and other companies. JVM’s implementation is known as JRE (Java Runtime Environment).

Whenever you write a Java command on the command prompt to run the Java class, an instance of JVM is created. While talking about these aspects, developers have the leverage of choosing two big programming languages: Kotlin & Scala.

So, before exploring Kotlin vs Scala comparison let’s take you to their aspects such as concepts, features, and deciding factors.

What is Kotlin?

Kotlin Vs Scala

Kotlin programming language, which implies it operates on the Java Virtual Machine and compiles down to Java byte code. As a language, it’s very similar to Java. So if you’re a Java programmer already, then using Kotlin is not a large step unlike, say something like Scala where you might have to learn many more new concepts.

In Kotlin it’s fairly easy to get started straight away just by applying what you already know from the Java language. Kotlin is an object-oriented language. So we can create classes. We have methods within those classes. We can new-up instances of those classes. We can create objects. It’s a standard object-oriented language.

However, Kotlin was also designed to be a functional JVM programming language. Due to this, Kotlin has support for higher-order functions. So developers can store functions in collections. They can pass a function as a parameter to another function. And also return functions from other calling objects. So, functions within Kotlin are treated as first-class citizens.

Kotlin has less ceremony than Java. So in Kotlin if you want to create a property, you just declare a file or a var, and that will declare me a property that’s either read-only or read-write. There’s no need to declare a variable and then have a get method and a set method.

Under the covers, Kotlin programming language will generate getters and setters, so those properties are usable from Java. But that’s just one example of where you need less code in Kotlin to do the equivalent thing in Java.


Concise Code

Developers always love clean and concise code. Less code takes less time to write, and less time to read and also makes it easy to maintain it.

Kotlin is a concise code compared to Java. It drastically reduces the amount of boilerplate code. So, compared to Java you will write a less amount of code in Kotlin, which increases the speed of your development.

Rough estimates indicate that Kotlin programming language requires 40% fewer lines of code compared to Java.

Null Safety

More than 70% of Android apps crash due to the null pointer exception of Java. Java does not provide any ways of protection against the null. The developer has to handle it on his/her own.

But Kotlin handles nulls nicely. In Kotlin you cannot get a null pointer exception implicitly. Kotlin compiler by default doesn’t allow any types to have a value of null at compile time. So if you use Kotlin then it will reduce your app crashes and gives a better user experience to your user.

Expressive Code

Expressive code means code that can be easily understandable by every programmer. Kotlin programming language is expressive. All data types, built-in functions, keywords, etc. are very expressive and easily understandable.

Kotlin is designed in such a way that even a person who never codes in Kotlin can easily understand its code.

Modern Features

As Kotlin is a fourth-generation language, it introduces and combines a lot of new features like Lambda functions, smart casts, null safety, operator overloading, etc. Which will help you in increasing your productivity? Kotlin is influenced by six major languages and it inherits a lot of the best features of them.


Functional Approach + OOP Style

Any Java competitor has to be an FP language. Kotlin lacks a little with these concepts and types of safety, but it offers all the features of an OOP-style language with an FP approach.

Higher-Order Functions

The convenience of higher-order functions is very well-preserved in the Kotlin programming language. In case you are unaware, higher-order functions are such functions that take a function as an argument and return type.

Backed By JetBrains & Google

Although in Kotlin vs Scala, Kotlin has the support of two great companies: the formidable Google and the amazing JetBrains, who are responsible for many other IDEs, including the IntelliJ IDE for Android.

So there is no doubt about great tooling support there. To all the people who thought of Kotlin as some trend, you could not be more wrong.


Extra Runtime Size

If your applications are already long, then the extra runtime size of 800KB could be a problem for you. You might experience a dwindling number of downloads because of the bigger size of an application.

Initial Readability Of Code

Nothing is ever all good. With the concise approach Kotlin offers, there is a little problem. With so much going on in so little code, it becomes a little hard to read and understand at first. It might even feel overwhelming to a beginner.

Lack Of Official Support

Although Google has joined hands with JetBrains to offer support for Kotlin, it is pivotal to know that Google does not endorse it. Even when you use Kotlin in Android, the autocorrect occurs slower than it does for Java.

Smaller Support Community

As I already mentioned, Kotlin is younger than Scala language and, needless to say, Java. Since Kotlin is younger than Scala, it has fewer libraries, blog posts, and tutorials. The online support community is quite small.

The lack of blog posts, tutorials, and user documentation might become a problem for you, but as trends suggest, this might be filled up soon as more and more people and companies are adopting Kotlin.

What is Scala?

Scala Programming Language

A Robust and High-Caliber programming language that changed the world of big data. Scala is capable enough to outrun the speed of the fastest existing programming languages. Scala is a compiler-based and multi-paradigm programming language that is compact, fast, and efficient.

The major advantage of Scala is that it is the common JVM language for app developers. Scala code is first compiled by a compiler and the byte code for the same is generated, which will be then transferred to the JVM to generate the output.

Moreover, if you are looking to execute an Android app development project then you might find this language productive and effective.



It is pure object-oriented language in the sense that every value is an object. The type and behavior of the object are described by classes and traits. The name Scala is the abbreviation of the term Scalable Language.

Scala is one of the modern multi-paradigm JVM languages designed to express common programming patterns in a concise, elegant, and type-safe way. It smoothly integrates features of an object-oriented and functional language.

Scala Is Functional

Scala language is also functional in the sense that every function in a Scala is a value and every value is an object, which makes every function an object.

It provides a lightweight syntax for defining anonymous functions, also called Function literals. Function literals are nameless functions. Their concept and use of Arrow syntax have many names like – lambda expressions, lambdas, function0, function1, function2…..

Scala Is Statically Typed

Scala, unlike some other statically typed languages (c, Pascal, rust, etc.), does not expect users to provide redundant type information. They need not specify a type in most cases, and certainly, don’t have to repeat it as well.


Full Support For Pattern Matching, Macros, & Higher-Kinded Types

Pattern matching in Scala language is no joke. It uses the match statement for this purpose, which is a powerful version of Java’s switch statement. It allows you to match any type of data, lists, and even your types. If you haven’t already tried it, I suggest you play around with it a little.

Write Once, Run Everywhere

Scala is a little complex, but it has a very flexible code syntax. The proficient use of functional programming features makes the code extensible and hierarchical to the very best level.

Bigger Community Support

Scala programming language has been here for more than a decade. Since it is a powerful Java alternative, it has a huge support community. We’re talking about YouTube tutorials, blog posts, forums, and let’s not forget the official support and user documentation. Anything you find yourself struggling with, you can pretty much find the answer to it.

Object Overloading

Scala does not restrict you from overloading operators. You can play with object-based functions and define limitlessly. But you need to be careful with this feature. Still, if you can do this right, your code readability will increase. If not, you might end up making your code difficult to understand.


Slow Compilation

Everything is about speed in the world of coding. A slow program is a big turn-off. When it comes to industry-grade projects, Scala’s compile time turns into minutes as compared to Kotlin, which tries to compile as fast as Java, which is in seconds.

Binary Compilation Is Challenging

Scala is not binary-compatible with a few versions. Let’s say you compiled with Scala 2.1. The same will not compile with Scala 2.11.

That could be nothing, or it could be your biggest nightmare if you have to work across different versions and update them. Especially if you have production-Scala projects.

Less Efficient In The Management Of Null Safety

Scala attempts a good take on managing null safety, but it’s just not as effective. The Scala equivalent for null safety is the Options keyword. Using this, there is a considerable chance you might get an NPE at the back door.

As elaborated above, you will finally have a full set of comparative factors to decide which one will lead toward a successful end product effectively. Kotlin vs Scala is always a close fight, especially when app developers take this task seriously for their projects.

So, let’s move forward toward exploring which one will dominate at the end of this comparison.

Comparative Analysis

Worldwide Users

The lifespan of Kotlin and Scala languages is big as worldwide developers and companies know their extensibility. Scala has been around since January 2004. Kotlin’s first appearance was made in 2011.

It’s only logical that Scala has more resources as it had less competition in its earlier years and has had longer to build a community. However, there have been some key events that have helped the Kotlin programming language gain a lot of traction.

The biggest event was Google adopting Kotlin for the Android Operating system. We can leverage search data from Google Trends to get a general idea as to the interest of both languages over time.

Overcoming Benefits

One of the benefits of Kotlin being built on top of Java is that its standard library is extremely lightweight. As mentioned above, the .jar on my MacBook weighed in at only 1.2MB. Scala, on the other hand, doesn’t extend Java the way that Kotlin does.

It offers its solution to the constraints imposed by the JVM and is much bigger .jar (albeit still relatively small in the grand scheme of things).

Compatibility Check

At the end of the day, you might need to run both a Kotlin API and a Scala API on the $5/month Digital Ocean droplet with no issues. The size of the .jar seems to be negligible for most developers but it is worth mentioning if you’re targeting older or lower-performing devices.

Access To Libraries

It feels strange to say this: But JVM programming languages just wouldn’t feel viable without libraries and frameworks written by the community. That’s a huge part of what makes them worth picking up!

Take, for example, Ruby. Ruby would not be where it’s at today without Rails. This is arguable for the same related to Java and Spring. Even the same for Python and Django!

However, that’s not what we’re here to learn about. We’re learning about the popular libraries available to Kotlin and Scala Developers. And we’ll get right into that one thing: As long as you’re targeting the JVM languages, you can use existing Java libraries and frameworks in both Scala and Kotlin.

Who is The Winner?

Building an application or web-based solution using JVM requires an understanding of core programming concepts. Choosing the right JVM languages will help to reach the exact end product for the success of the project is mandatory.

The Kotlin vs Scala comparison in this guide makes way for a close fight between both languages. However, developing web-based and mobile-based applications is a huge task that requires playing with a handful of datasets, functionalities, and some major modules.

Due to this, the Scala programming language seems to be the nearest to the finishing line in this race. Yes, the comparison held in the above guide results in this conclusion, and that’s why the hype on Scala’s extensibility also gained a great response.

Chandrapal Singh
Chandrapal Singh

Director at Appventurez

Director and one of the Co-founders at Appventurez, Chandrapal Singh has 10+ years of experience in iOS app development. He captains client coordination and product delivery management. He also prepares preemptive requisites and guides the team for any possible issues on a given project.

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