Incorporating Kotlin in Your Large App – How to Go About It

Moving an existing large app to a new language can seem like a daunting task. The recipe for success in such a case is to start slow, move in chunks, and test frequently to align your team for success. Kotlin is a modern, concise, and lightweight Android language that has in very little time become the second most used programming language after Java. 

Kotlin app development and deployment is faster to compile when compared to Java. Being lightweight, it prevents applications from increasing in size. In fact, any chunk of code written by hired Kotlin developers is much smaller when compared to Java, as it is less verbose. At the same time, less code leads to fewer bugs, which is an additional plus. Kotlin Android development companies compile the code to a bytecode, which can be executed in the JVM.

Kotlin is fully interoperable with Java and is easy to migrate to. A series of steps need to be followed in order to incorporate Kotlin in a large app. Here’s a guide to help you successfully incorporate Kotlin on existing large apps:

1. Build a Team

The first step before migrating is to build a common baseline understanding for your team. You can start by designating a person in your team to become the Kotlin expert and mentor to lead the learning efforts.This individual should focus on learning as much as possible and become the subject matter expert. They should proactively share their Kotlin knowledge, and become the “go to” person for any questions from the team. Ideally, this person is already passionate about Kotlin and has some working knowledge.

2. Learn the Basics

If your team is just getting started with Kotlin there are a lot of resources you can use to learn the language and how it interacts with Android.

3. Form a Study Group

Study groups are an effective way to facilitate learning and retention. Regular group discussions help you understand upcoming language features and reinforces Kotlin best practices at your company.During each meet, the group can compare what they’ve learned and discuss any questions or observations.

4. Introduce and Integrate Slowly

As an organization planning to make such a major shift, it is important to start slow and think strategically about what parts of the ecosystem to move first. Before converting existing Java code to Kotlin, start by adding small pieces of Kotlin code to your app’s codebase. Begin with a small class or top-level helper function, making sure to add the relevant annotations to the Kotlin code to ensure proper interoperability from the Java code.

5. Periodically Analyze the Impact of Change on App Performance

Adding Kotlin to your app may increase both the APK size and build times. For Kotlin-only projects and mixed-language projects (that are written in Java and Kotlin) there is a slight increase in compile and build times. However, many developers feel that the increased productivity of writing in Kotlin is a worthwhile trade-off. Continually strive to improve the Kotlin app development process, and timely measure and monitor the build performance impact on the app.

6. Update All Existing Code to Kotlin

Once the internal team is comfortable with using Kotlin, you can now convert the entire existing code to Kotlin. As Kotlin and Java are fully interoperable, you can easily migrate your project one class at a time. While the interoperability is 100%, the same is not true for source compatibility.

7. Define Project-specific Style Conventions

The Kotlin and Android have specific style guidelines that can be established as great baselines for formatting Kotlin code. It helps to establish conventions for your team to follow so that there is uniformity in the final product. Kotlin provides great style defaults that follow standard Kotlin style guides that can also be customized to your team’s specific needs.

How to incorporate Kotlin into an Existing App

There are a few things you can do to attain consistency in your project as your Kotlin code base grows:

  • Common coding standards

Be sure to define a standard set of coding conventions early on in your adoption process. You can diverge from the Android Kotlin style guide where it makes sense.

  • Static analysis tools

Enforce the coding standards set for your team by using any static analysis tools. 

  • Continuous integration

Be sure to conform to common coding standards, and provide sufficient test coverage for your Kotlin code. Making this part of an automated build process can help to ensure consistency and adherence to these standards.

  • Interoperability

Kotlin interoperates with Java seamlessly for the most part, but it is not compatible at the source. Kotlin relies on the ability to null annotations in compiled code to infer nullability on the Kotlin side. If annotations are not provided, Kotlin defaults to a platform type which can be treated as the nullable or non-nullable type. This can lead to runtime NullPointerException issues, however, if not treated carefully.

While the entire migration process to Kotlin might seem like a daunting task, it is definitely a rewarding one. Every business that has undergone this transition has been reaping the benefits of the shift. Kotlin, being a relatively new language, is much more suited to cater to the needs of the new age apps. It has been deemed as a modern statically typed programming language, and is being used by over 60% of professional Android developers currently. Kotlin has been proven to help boost productivity, developer satisfaction, and code safety and is being adopted all over the world as one of the best languages for Android apps development.