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5 minutes read

Kotlin Vs Java – Comparing Programming Languages

By Mario Tatis
By Mario Tatis
App Development
5 minutes read

The Kotlin vs Java dilemma is one that many Android developers have to face on a daily basis. Both are great programming languages for Android app development, and this is probably the root of the problem. How can developers choose between two alternatives when they are both very good at what they do? More importantly, which one should you choose for your company’s Android app development project?

Even experienced developers have a hard time when it comes to choosing between Kotlin or Java. If you’ve been wondering what the differences are between Kotlin and Java, or which of them should you use for your Android app, then this post is for you. Don’t worry, I won’t go too deep into the technicalities of the debate.

Kotlin Vs Java: Which Is the Best?

Before I go on to explain the differences between Java and Kotlin, there is one thing that you should know. Very often, people ask whether one programming language is better than another. Most of the time, this is the wrong question to ask. Different programming languages exist for a reason: they all have unique properties. In other words, each has unique characteristics that distinguish it from others. This not only applies to the Kotlin vs Java debate, but also to other cases.

For the case of Android app development, this comes with a disclaimer. In recent years, Kotlin has been gaining popularity for important reasons. To understand this phenomenon, it is best to analyze each individual programming language. Although you should definitely decide the right alternative that best suits your specific Android app development project based on your actual needs, more likely than not the right choice will be Kotlin.


Java is an open source programming language initially developed by Sun Microsystems and released in 1995. It is an object-oriented language that has been used to build some of the world’s most popular apps, including the Android operating system. It can also be used for web development and enterprise software. 

It is designed to run on what is known as the Java Virtual Machine (JVM). This gives Java a major advantage as it can run on any computer, making it easy for developers to follow the write once, run anywhere philosophy (WORA). However, the Java Virtual Machine can also be used by other languages that can be compiled into Java bytecode. Kotlin happens to be one of them.


Kotlin is a pragmatic open source programming language designed to work with the Java Virtual Machine and Android. Because of this, and other reasons, it is a strong alternative to Java as the de facto language to build Android apps. It can use anonymous functions, extension functions, high-order functions, and many other functional programming characteristics.

Among its other characteristics, it is worth mentioning that Kotlin can be compiled to JavaScript, a language that has been gaining popularity in recent years. Because Kotlin is also object-oriented, it can easily replace Java-based code thanks to what is known as interoperability

Kotlin Vs Java – What Makes the Difference?

There are important differences when it comes to the Kotlin vs Java debate. If there’s only one that you ought to remember, I’d say it is this: Java is not a modern language, while Kotlin is. Although Java has a big community of developers who constantly work to improve it and build new products, its syntax is not very friendly. Java, for example, is known for its boilerplate code which makes it sometimes very repetitive and inefficient at the moment of writing the code. This means that its code has to be written or repeated many times even if it does not fulfill a main task in the program itself. Kotlin, on the contrary, can help developers avoid boilerplate code, helping save time when coding through more efficient data classes. Similarly, cast operators work better in Kotlin; these convert one type of data to another. Kotlin does this in a more efficient way thanks to smart casting, a way to transform one type of data to another in an easier way than Java.

Additionally, certain limitations between the different versions of Java and the Android OS exist. This is not the case with Kotlin. Although developers need to configure Android studio to work with Kotlin, this last will not have the same limitations as Java in terms of code execution. The best part is that, thanks to the aforementioned interoperability, your Java libraries, Android extensions, and other resources can be used when working with Kotlin without inconveniences. You can even convert Java files into Kotlin using Android studio. 

Kotlin Vs Java: Important Factors to Consider 

Your Android app users won’t notice any difference between building your app using Java or Kotlin. They will most likely use the app in the same way. The real difference lies in the app development process. For your company, using Kotlin instead of Java will surely mean less developer hours, which in turn translates into important savings. 

This is the real reason why many app development companies are opting for Kotlin as the preferred choice at the moment of developing Android apps. As mentioned at the start of this post, both programming languages are very powerful. There’s really no way to tell who’s the winner of the Kotlin vs Java debate. It is, ultimately, a matter of choice even if the benefits are clear. Discuss with your app developer why Kotlin might be the best choice for your company and you will be surprised by the benefits.

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