Kotlin vs Scala: which is the best JVM language for developing Apps?

Kotlin vs Scala, which should be the next ruler of your code? Scala vs Kotlin, who will get the title of “Better Java” with each bringing something unique to the fight? These languages have become popular in recent years, and both have the potential to build robust and scalable applications. That’s why most people are confused about Scala vs Kotlin, which one is best for their project. We have come up with this blog post to provide a comprehensive guide on Kotlin vs Scala to help you decide which language Scala vs Kotlin to choose for your project depends majorly on your project motive and requirement.

“Old is Gold”, the same we can say for Java. 

But what if we get some advanced features with basic old functionality(Java). 

Isn’t it interesting? Yes!

Scala and Kotlin are better and newer Java. Each of them adds and expands on the capabilities of Java in its own way. But don’t worry; after reading this blog, it will be easier for you to decide which one can skyrocket your project. Let’s go through the Scala vs Kotlin table for a quick overview.

Before diving deep into the Kotlin vs Scala differences let’s get acquainted with the history of both these languages. 

Kotlin vs Scala: Overview

Overview of Kotlin

Kotlin was started by JetBrains in 2011. JetBrains, the same company behind IntelliJ IDEA, has been open source since 2012. It is a general-purpose, open-source, statically typed programming language. Kotlin is initially designed for the Java Virtual Machine (JVM) and Android that combines functional programming and object-oriented features. 

We can say that Kotlin is a multi-paradigm, object-oriented programming language that tends to be the improved form of Java. That’s why this language is mainly focused on interoperability, clarity, tooling support, and safety. Kotlin provides the most advanced features such as concurrency, serialization, etc., using 3rd party libraries.

One of the best benefits of Kotlin is it supports multi-platform programming. It means we can effortlessly compile the Kotlin source for other platforms. Upcoming versions of Kotlin targeting JavaScript and native code for a number of processors are in production as well. 

Overview of Scala

In 2004, Martin Odersky released an updated version of Java, called Scala. The name is derived from the scalable language- Scala. It is a statically typed general-purpose programming language. Like Kotlin, Scala supports both functional programming and object-oriented programming. 

Scala source code can be compiled to Java bytecode; hence it can run on a Java virtual machine (JVM). This language adds various features that are not present in Java, such as optional parameters, named parameters, operator overloading, and raw strings. It also provides language interoperability with Java, due to which libraries written in either language may be referenced directly in Java code or Scala.  

Now you have a general idea about the origin and features of both languages. However, coming to Scala vs Kotlin, the best part about Scala is that it is somewhat similar to Java. That means you can easily get a hand on Scala if you are familiar with Java. Hence, in Kotlin vs Scala, we can say that by using Scala, you will get more functionalities and features in your application than Kotlin as it can be combined with Java bytecode which further adds various features that aren’t present in Java. 

Moving further, we will have a detailed discussion about Scala vs Kotlin. This guide will help you to identify which language could be useful.  

Kotlin vs Scala: A Complete Comparison Guide

This is a comprehensive guide regarding Scala vs Kotlin comparison to answer many of your queries.

It’s time for an intense fight between the topmost JVM languages: Kotlin vs Scala.

Mode of Comparision

• Popularity
• Functional Programming
• Learning Curve
• Java Interoperability
• Pattern Matching
• Community Support
• Operator Overloading
• Inlining
• Data Classes
• Tooling support

Let’s dive deeper into these comparison parameters and determine out of Kotlin vs Scala which one is best for your application development.

1. Popularity

Check out the popularity of both languages on Google Trends, GitHub, and Online Job Portals.

• Google Trends

Looking at the Scala vs Kotlin graph, we can say that Scala is more trendy than Kotlin.

• GitHub

Find out the GitHub stars and contributors of Kotlin vs Scala in the given table.

Kotlin vs Scala: GitHub stars and contributors

• Online Job Portals

Kotlin vs Scala: Number of Job Posting in USA

(Note*- Data derived from the respective website as on May 2022)

Considering the job posting on these three platforms, amongst Scala vs Kotlin, Scala is the clear winner.  

2. Functional Programming,

While both these JVM languages are known for the functional programming paradigm, Scala is the winner between Kotlin vs Scala in terms of functional programming. Let’s see, Compared to Kotlin, Scala is more affected by functional programming languages such as Haskell. Scala also encourages the use of functional coding along with various other features like currying and pattern matching. Additionally, in the Scala environment, the attempt of possible functional programming is more considerable than in Kotlin. 

3. Learning Curve

According to the Java developers in various web development companies, one can easily understand and learn Kotlin’s basic syntax in a few hours and can easily start coding in just a couple of days. Additionally, various free courses provided by Google help developers to get used to  Kotlin faster.

On the contrary, Scala is a powerful language with advanced features and flexible syntax. Hence it is quite difficult for newbies to get their hands on to JVM programming language.

No wonder Kotlin is super easy to learn as compared to Scala in Scala vs Kotlin.

4. Java Interoperability

Although both Kotlin and Scala are interoperable with Java, but in the case of entire compatibility requirements with existing Java-based projects, then Kotlin is the winner between Kotlin vs Scala. You can effortlessly call Java code from Kotlin and Kotlin code from Java. If you need Kotlin for server-side development, you can use existing Java-based frameworks like Java Server Faces (JSF). Talking about Scala, you may not find any issue accessing Java classes from Scala code. But if you are using some of Scala’s more advanced features, you may run into problems because these advanced features lack Java equivalent.

5. Pattern Matching

Out of Kotlin vs Scala, Scala offers more opportunities for pattern matching. Its match statement allows developers to match any type of data along with their own data. Moreover, Scala shows full support for higher-end and macros types. This is the reason Scala is considered a perfect fit for Big Data processing tasks. Kotlin, on the other hand, does not completely support pattern matching.

6. Community Support

Kotlin came into the market in 2011, while Scala made its first public appearance in 2004. Being in the market for more than 15 years, Scala has a bigger community than that Kotlin. Kotlin, on the other hand, has fewer community resources such as native libraries, tutorials, blog posts, etc. In case you are looking for something not included in documents of both these JVM languages, you may find it more troublesome to find it at that moment if you choose Kotlin rather than Scala. Hence it is feasible to select Scala in Scala vs Kotlin for larger community support.

7. Operator Overloading

Operator overloading redefines an operator’s behavior for a particular type to create user-defined implementations of various operators. Surprisingly! Java does not support operator overloading, but both Scala and Kotlin are loaded with this functionality. Let’s see which JVM language Kotlin vs Scala is the winner in terms of this functionality.

Kotlin operators are Quite easy to understand, even for newbie developers. However, Kotlin tries to maintain a balance between power and readability by enabling developers to overload the basic operators already in the language but prevent them from defining the new ones. Hence, in Scala vs Kotlin, Kotlin’s operator overloading is less flexible than Scala. 

Scala goes with a more lenient approach to operator overloading. It allows developers to define an unlimited set of operator-looking functions. Hence using Scala, developers can effortlessly write highly readable codes. But in case it is used incorrectly, it can create confusion as well. All in all, we can say that Scala is the winner of operator overloading in context to Scala vs Kotlin.

8. Inlining

Inlining is an optimization that allows you to remove call overhead by replacing a function call site with the actual function code. This inlined function runs faster than the normal function. Hence with the help of inlining functions, lots of minor tweaks to your code can add up to a significant performance boost. Java’s compiler performs inlining automatically, but there is no way of doing it manually. But you can gain the ability to inline functions manually if you switch to either Scala or Kotlin.

Talking about Scala, the compiler has the choice to see if the function is actually inlined or not. The developers can request the compiler to inline a method by annotating it with @inline.  For example:-

@inline final def1(x: Int) = x

While in the case of Kotlin, the compiler considers all the functions automatically with the ‘inline’ keyword as inline. Hence developers need to be a little bit more careful to avoid the risk of inlining duplicacy.

Coming back to Scala vs Kotlin, Scala exceeds Kotlin, becoming an exceptional choice for developers. 

9. Data Classes

Kotlin’s data classes and scala’s case classes serve a similar function. Both of them enable you to represent a data-holding object with no requirement of writing a ton of boilerplate code. By annotating a regular class with the ‘data’(Kotlin) or ‘case’ (Scala) keyword triggers auto-generation of lots of boilerplate code associated with DOM (Data Object Model) such as toString, plus accessor methods and setters, equal, and hashCode. While discussing Kotlin vs Scala, Kotlin doesn’t automatically infer the constructor parameters; hence you have to declare them as either var or val. Let’s take an example to understand Scala vs Kotlin data class compassion parameter in a better way. 

Scala case class-

case class Date(month: String, day: Int)

Kotlin equivalent would be 

data class Date(var month:String, var day: Int)

10. Tooling Support

We all know that good tooling support eases our work; hence it must be the major factor while deciding the programming language for your application. From Kotlin vs Scala, let’s determine which one comes with more tooling support. Since day one, JetBrains, the company behind Kotlin, has focused on good tooling and support as the main goal. In 2017 Google announced first-class support for Kotlin on the Android platform. Hence the tolling support in Kotlin is great and helps developers to develop applications fastly yet efficiently. 

Back in 2004, when Scala arrived, you got only a command-line compiler as the tooling support. At that time, Scala core developers preferred to write their code in emacs until a robust and stable Scala IDE for Eclipse was available in December 2011. Today Scala comes with lots of supporting tools and plugins. For example- the plugin for the IntelliJ IDEA is very mature. So, if we talk about Kotlin vs Scala, the verdict is ‘Tie’ as both languages provide great tooling support.

Kotlin vs Scala: Strength and weakness

The upcoming section on Scala vs Kotlin strengths and weaknesses helps you identify and understand how these languages can be game-changers for your business.

Kotlin Strength

• Corporate Backing

The great support of Google or JetBrain provides an undeniable advantage to Kotlin. 

• Concise Coding

One of the main drawbacks of Java covered by Kotlin is boilerplate code. With fewer code lines in Kotlin, bugs are also fewer, and written code is easier to read. 

• Functional Programming Approach + OOP Style

Although Kotlin lacks the higher-kinded types and types of safety, it offers all the features of an OOP style with an FP approach. 

• Great Java Interoperability,

The biggest strength of Kotlin is its high compatibility with Java code. Developers can easily call Kotlin code from Java and Java code from Kotlin without much effort. 

Kotlin Weakness

•  Inferior Pattern Matching

In the case of Kotlin, pattern matching is not fully supported. It is somehow possible to achieve a similar result with a smart application of the when clause, still Scala wins the race in terms of pattern matching. 

•  Limited Usability

When it comes to Android development, of course, Kotlin is a perfect choice in every way. But in the case of other applications, Kotlin is not as useful and applicable as Scala. 

•  Smaller Community

Although Google’s support of Kotlin enhanced its popularity still, it lacks community support. With fewer tutorials, tools, and expert support, dealing with any issue in Kotlin is a big deal for developers. 

Scala Strength

• Bigger Community

Scala has been in the market for 15 years, and many developers have worked with it. That’s why lots of resources, tutorials, and useful answers are on various public forums like StackOverflow, Reddit, etc. 

• Pattern Matching

Scala’s match statement offers full support for macros and higher-kinded types; hence it is ideal for big data processing tasks. It lets you match any type of data, including its own type. 

• Flexible Syntax

Scala provides high flexibility in coding. Its coding is based on writing once and running anywhere and combining it with a functional coding style, making Scala the best choice for newbie developers. 

Scala Weakness

•  Inferior Java Compatibility

If you want to go back and forth between advanced Scala code and legacy Java code, you might find it troublesome. As compared to Kotlin, Scala introduces functional programming and classes; that’s why you might get some errors when calling from Java. 

• Slow Compilation Speed

One of the most significant weaknesses of Scala is its slow compilation. In the case of complex enterprise-grade programs, Scala takes a long time to compile compared to Java and Kotlin.

• Null Safety Management Inefficiency

Compared to Kotlin, many developers find Scala’s approach naïve and incompetent. To deal with NPE, Scala substitutes null values with the option. This adds some major complexity to the code as it requires it to be used explicitly.

Kotlin vs Scala: Why and where to use it?

In context with Scala vs Kotlin, you can brainstorm your application requirements and identify how these languages could be useful. Moreover, you will be able to recognize the best language out of Scala vs Kotlin.

Why use Kotlin?

Kotlin is more concise than Java and easier to learn and use. The concise syntax implies you have to write less code. This is good for newbies because, with Kotlin, they can get up and running faster with fewer lines of code. Besides, the higher interoperability of Kotlin with Java allows developers to mix both languages in the same project effortlessly. As Kotlin uses IntelliJ IDEA for our development environment, Android Studio has excellent support for Kotlin already built-in. For that, you just need to access certain additional plugins to take its entire leverage.

What are the uses of Kotlin?

Following are the use case of Kotlin:

• Due to its high interoperability, Kotlin is best for projects where some parts are written using Kotlin and others are written using Java programming language.
• It runs perfectly alongside various other modern programming languages called Swift. Swift can be used on devices with iOs, IPadOs, WatchOs, tvOS, Linux, Windows, or macOS.
•  It is the perfect choice for people who are relatively new to programming or coming from other languages like JavaScript, Ruby, etc.
• It is best for newbie developers as it reduces boilerplate code and has a short learning curve. 

Why use Scala?

Scala programming is useful when it comes to object-oriented and functional programming as it allows you to use the best of both worlds. Scala uses an OOP syntax that provides a lot of flexibility in terms of functional programming. Due to its very strong focus on functional programming, it stands out from many other languages such as Java and C++. The functional approach implies that you get to clean up your code because the language is built around immutability and, whenever possible, avoiding state mutation. This helps developers to write code quickly while at the same time avoiding bugs. 

What are the uses of Scala?

Following are the use case of Scala:

• Due to its concise, efficient, and straightforward code, Scala is best for both small and large teams. 
• It is perfect in case you are looking for better speed while allowing you to write clear code with fewer bugs.
• It is best for building complex, multi-threaded systems. 

Kotlin vs Scala: What do APPWRK developers think?

After reading this blog, we hope you have a fair idea about both of these JVM languages. You are now clear about the benefits of using one over the other. According to APPWRK proficient mobile app developers who have worked with both these languages, which language to choose for your project depends majorly on your project’s motive and requirements. With each programming language having its own advantage and disadvantage, the decision is made based on who caters to your business needs in the best way.

Hence in Scala vs Kotlin, Kotlin is the best choice if you need to use existing Java libraries, while Scala is the better option if you are into functional programming. The main point here is to consider which programming language will go best with your project before making any decisions about using either Kotlin or  Scala.

We believe that you find this Scala vs Kotlin guide informative, still, you have any doubts feel free to reach out to APPWRK.