Java vs Kotlin: Choosing the right language for mobile app development

Samitha Kuruvitaarachchi


4 mins

Developing Android applications is a great option to drive success to your business but picking the best programming language can be a  real dilemma. To many of us, it was evident that Java is the best choice as it is everywhere and everyone praises it. However, after the arrival of Kotlin, this apparent belief in Java was somewhat shaken and programmers started questioning between the two. In order to resolve this dilemma of Kotlin and Java, and to give you a clear understanding, let's discuss which is the best for Android development.

What is Java?

Both languages have their pros and cons

Java is a native programming language used by Android developers, to develop applications that communicate with the operating system and directly use the hardware. It allows the creation of any type of program and supports almost all types of machines and Operating Systems.

Benefits of Java

  • Java is multiplatform and works on practically any device, server or operating system.
  • Java is an object-oriented language and makes it easy to create modular applications and reuse the parts.
  • It is ready to use - with Java, you will get a lot of third-party code and modules that are ready to use.
  • In comparing to Kotlin, Java is easy to use, compile, and makes debugging and deploying even simpler.
  • Java is an open source language that ensures safety, since many of its libraries are managed by trusted companies like Google, Apache.

Even with these benefits, Java is facing some tough challenges. Including,

  • With Java, it’s impossible to access certain content that may be incompatible with the device or equipment being used.
  • Java is a bit slower with respect to other programming languages and takes a lot of system memory.
  • It isn’t easy to access the new Java enhancements in mobile developments.

What is Kotlin?

Major names are changing side

Kotlin is a newly created language that is inspired by Java, it’s an improved version of it with so many additional features. It’s clean, simple and carries fewer formalities and rules compared to Java. To use this language to program android applications, developers still need to understand basic programming concepts and structures.

What are the benefits of using Kotlin?

  • Kotlin application deployment is faster to compile, lightweight and prevents apps from increasing in size.
  • It’s safe against NullPointerException (The Billion Dollar Mistake).
  • Kotlin incorporates co-routines, as well as interoperability with JavaScript for web development.
  • Any chunk of code written in Kotlin is much smaller compared to Java and less verbose. Less codes means fewer bugs.

Kotlin faces more challenges than Java, because,

  • Kotlin is not so popular. So the developer community is sparse compared to a well-established language like Java.
  • It has a small support community as Kotlin is younger than Java, fewer libraries, tutorials and blog posts.
  • There are only a few Kotlin developers available in the market so finding an experienced mentor is quite tricky.

Feature showdown

Null Safety

NullPointerException or NPE is one of the main drawbacks of Java, this is caused by some data inconsistency related to variable initialisation or calling faulty external Java code. Kotlin, on the other hand, avoids NullPointerException at runtime. Kotlin fails at compile-time whenever a NullPointerException may be thrown.

Smart Casts

Kotlin's compiler is intelligent. In many cases, one does not need to use explicit cast operators in Kotlin, but in Kotlin vs Java, Kotlin has “is-checks” for immutable values, and inserts cast automatically when required.

Functional Programming

The most important thing in Kotlin vs Java performance is that Kotlin is a functional programming language. Basically, Kotlin consists of many useful methods, which include higher-order functions, lambda expressions, operator overloading, lazy evaluation and much more. Functional Programming makes Kotlin much handier when it comes to collections.

Type Interfaces

When using Kotlin, you don’t have to specify the type of each variable explicitly(in a clear and detailed manner). But if you want to define a data type explicitly, you can also do that.

So Which one is the best?

Kotlin is a rising star, but Java maintains its status as a top ranker

We side with Kotlin. This is so because Kotlin works with Java and provides incremental change of code and a superior type system to Java. It provides an easy migration path from Java with backward compatibility. With features like more declarative, less code, mixed language database Kotlin is more expressive than Java. Kotlin is the future language for enterprise applications and Mobile in comparison to Java.

Summing Things Up

We know that a clean build is done only one time in our project, and the Incremental Builds Compilation time is more crucial for us than a Clean Build. In this respect, Kotlin is almost the same as Java, but given all the other advantages we can go with Kotlin without worrying about Compilation time.

Samitha Kuruvitaarachchi

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