8. These are pure JVM projects. To support the generation of mixed source sets, we added support for specifying exactly which Thrift elements should be generated in each language. A majority of cross-platform solutions require you to write all your codes in the target language such as Xamarin. We are not sure how big of an impact this implementation has on the Kotlin plus Kapt build performance and could not gather data with the optimized version yet. Developers who love Java can continue using it, and also add Kotlin code incrementally and make use of Kotlin libraries. The “source” in “source code” is also significant here—the Kotlin compiler generates a number of synthetic elements that would otherwise need to be manually included in the equivalent Java source code. Robust Performance Kotlin is very suitable for cross-platform mobile app development because it compiles code according to the targeted platform. Unlike Java, Kotlin has a more expressive syntax like python. Structs/exceptions/unions are generated as standard value types (POJOs). Kotlin and Java files can exist together in Android apps. While Kotlin’s new type inference system is still experimental, it adds a number of new improvements. Figure 8: We measured project performance between Pure Kotlin with Kapt (pink) and pure Kotlin (blue) setups, on the left, and pure Java with Apt (brown) and pure Java (turquoise), on the right. To most accurately execute our tests, we needed to leverage non-trivial code we would use in production environments. Structs/exceptions/unions are generated as standard value types (POJOs). Afterwards, another part of the script was responsible for synchronizing the results repository and shipping the data to our in-house databases, where it could be analyzed. This is a good indicator that the experiment environment was well-controlled. Ionic: It tends to support Android 4.4+ versions, iOS 8+ and Windows 10. It can be also used for backend development using Java frameworks. In this table, the displayed compilation time for line one represents the average compilation time across all 354 projects for all experiment runs. Once all data was collected, it was assembled into a single JSON file and committed to a separate Git repository. . With that in mind, we did not want to rely on results that would be improved only by using those features. to keep up with the latest innovations from Uber Engineering. So, the winner of Flutter vs Kotlin multiplatform performance battle is the latter. As a first step, download the materials for this tutorial by clicking the Download materials button at the top or bottom of the page. «I believe the future is bright for Ktor! In addition, the experiment execution was too slow (on average, the experiment takes two hours to finish on CI hardware). Many of the users may use similar usernames to log in. Also, Kotlin developed apps are easy to customize and better in performance. Understanding how the aforementioned scenarios behave with these features might reveal designs that can boost compilation speeds, and hopefully, lead to discussion on how these tools can be brought to a wider set of build systems. informed our decisions for best practices for Android development. To declare or not declare the types might be a question that comes up while writing code. Moreover, since it is still incubating, we were not surprised to see that it runs slower than the other type inference systems we tested. We believe that this happens due to the following reasons: Even with these reasons, it is odd to see that pure Java plus Apt is much faster when compared to pure Java with no Apt (only a ~5 percent overhead). You can write in any language of your choice, be it Python, Java or C++. Marketing Blog, It is fast and able to complete tasks promptly. This is an important part of how build systems like Buck and Bazel work. Below, we highlight some additional design considerations and knowledge we had in mind before embarking on this project: Based on these considerations, we created a project generation workflow that enabled us to develop hundreds of models with which to compare build performance for our new Kotlin-based applications. A natural progression in the Android space was to start adopting. Since we cannot infer that the work performed by each thread throughout a build execution is deterministic, we do not want multi-thread mode to interfere with the times from the compiler thread. By using native controls and native modules, React Native improves on performance. That gives Kotlin hope for a broader future use apart from Android development. Improved performance of Kotlin/Native compilation and execution. It is expressive and concise and works with Java. This is great news for iOS app developers who wish that their apps reach Android users. Teams are smaller in the size and thus easier to manage. The manual trigger of the script would also consume a lot of an engineer’s time and decrease productivity since it prevents them using their laptop for other tasks. Additionally,  since code is generated, we can control the morphology of these projects; for instance, we can generate them with only Java code, or only with Kotlin code, a mix between the both of them, and enable or disable annotation processors, among other combinations. At the code generation level, we implemented support for generating Java and Kotlin code using. Figure 2, below, shows the distribution of the generated projects based on their size, as measured by the number of files. Kotlin/Native uses the compiler technology LLMV to compile Kotlin sources into stand-alone binaries for multiple operating systems and CPU architectures like iOS, Linux, Windows, Mac, and Webassembly. It is in Buck’s vision to not support incremental compilation, as it results in compilation states that are harder to reproduce (imagine the steps to reproduce a compilation failure having a lot of Git patches intertwined with build commands). Apple has come down hard on the side of creating something optimized and free of most of the chains C/Objective-C. Google (JetBrains, really) has come down equally hard on the side of integrating seamlessly with existing code. We hope that this analysis can serve as a north star for other organizations  who leverage Kotlin. This is very advantageous as it provides the level of performance at par with native app development. Learn more. Gradle incremental compilation. While signing up for an app, a big hassle that may be encountered is the addressing of a large audience. During this benchmark test, builds were clean and the cache was turned off. We generate one project per .thrift file, and projects can depend on other generated projects that match the Thrift “include” statements. comes with a standard set of checkers. The “source” in “source code” is also significant here—the Kotlin compiler generates a number of synthetic elements that would otherwise need to be manually included in the equivalent Java source code. To run our experiment, we took the following steps: A Python script orchestrated the experiment execution; the language of choice for this type of experiment has no impact on experiment performance and was chosen based on team familiarity. You can build iOS and Android apps at the same time using the same code base. Figure 8: We measured project performance between Pure Kotlin with Kapt (pink) and pure Kotlin (blue) setups, on the left, and pure Java with Apt (brown) and pure Java (turquoise), on the right. This article was written in collaboration with the Kotlin team at, At Uber, we strive to maintain a modern tech stack in all our applications. To facilitate the success of this adoption, we launched an initiative, in collaboration with JetBrains, to measure Kotlin build performance at scale across different project structures, a process that. Many Android developers agree that Kotlin makes development quicker and more fun. To give a better overview of the generated code, we’ve created. Kotlin multi-platform compiles the code exactly in the same format as the platform on which you wish to deploy. functions and destructuring component methods (though this language feature is only useful to Kotlin consumers). Who uses Kotlin Multiplatform Mobile. Other than that, they need a good bit of boilerplate to communicate with the platform code such as React Native. Because of this, Java is the favorite of many Android app developers. A natural progression in the Android space was to start adopting Kotlin, a modern multi-platform programming language and an increasingly popular alternative for Android development that fully interoperates with Java. This feature empowers Flutter to make a perfect option for MVP development and creating a prototype that is used for testing. The increasing number of custom checkers, along with the fact that we do not share their classloaders for different javac invocations, are likely responsible for the 70 percent overhead observed in this benchmark. At least from a build performance perspective, it doesn’t matter whether or not implicit or explicit types are used in the code. This entire process was run in the CI environment every two hours for about two weeks. Not anymore. An optimized implementation would have all Kapt stages and compilation to run in single `kotlinc` call. A Kotlin code offers more safety and concision in comparison to a Java code. We have more than 60 custom checkers that can get triggered hundreds of times every day to prevent a number of bugs. 5. I recorded some results and i found that swift is faster when the size is around 10000 or less but once the number goes up, Swift becomes significantly slow as compare to Kotlin. . Also, annotation processing was designed for Java and can run in-process with the javac compiler, as both share the same AST. We wanted to measure pure kotlinc/javac performance, and as such, did not use Kotlin’s. Join the DZone community and get the full member experience. It takes a Java developer just a few hours to learn Kotlin. At least from a build performance perspective, it doesn’t matter whether or not implicit or explicit types are used in the code. Both languages are as concise and transparent as possible. Both are free and open-source with support from a wide range of libraries and modules. Build times are tightly coupled to the build system in use, e.g., Gradle Incremental Builds or Buck Parallel building. Uber already used Buck as our Android/Java build system, so we did not test using tools like the Kotlin Gradle daemon and incremental Kapt. The apps enjoy the intuitive and robust features of native apps without compromising on the performance, all in a reduced timelines, cost, and resources. Kotlin with Kapt adds a ~95 percent overhead when compared with pure Kotlin only. This entire process was run in the CI environment every two hours for about two weeks. Because of this, Kotlin is useful for not only new apps, but also expanding existing Java apps. ), and fine-grained arguments and language controls to the code generation. Having a solid pipeline producing data is the best way to understand the impact of new features in your environment. A coroutine is a concurrency design pattern that you can use on Android to simplify code that executes asynchronously.Coroutines were added to Kotlin in version 1.3 and are based on established concepts from other languages.. On Android, coroutines help to manage long-running tasks that might otherwise block the main thread and cause your app to become unresponsive. To simplify this setup, we created a `BuildPerfType` enum with the aforementioned matrices, and added a `–build-perf` option to the project generation CLI. This is exciting for mobile app development as maintaining an app across Android and iOS can become more intuitive. I tried sorting an array of size 100000000 in Swift and Kotlin and i can see a huge performance gap between them. Overall, Kotlin resulted in 40 percent fewer lines of source code than Java, Kotlin is well-known for being able to achieve more with less code, and our experiments were a testament to this common knowledge. We wanted our analysis to be build system agnostic and keep the focus as close to kotlinc vs. javac as possible. On the other hand, Google recommends Kotlin as the standard IDE for Android development. As this analysis is non-conclusive, we opted to leave it out of this article. It is a lot easier to go for totally Kotlin-based apps and communicate with the same language in the backend, rather than providing an interpreter. It reads from a directory of Thrift specs, infers project dependencies, and then generates a flat set of projects that reflect those specs. Being already steady for a couple of years now React Native- a framework created by Facebook, is a popular choice for mobile applications development. Both are considered to be very secure and reliable for big projects. The debate of whether to choose Java or Kotlin has been very common in the Android community. Published at DZone with permission of Navya D. In 2019, more enterprise leaders are migrating to Kotlin or planning to do so. To support Kapt-less generation, we implemented support for optional direct generation of classes that would otherwise be generated during annotation processing. This is harder to optimize with Kotlin. Kotlin apps are also faster to build and require fewer resources than native app development. In iOS, generally, the hooks provided match the lifecycle of the view, creating an intuitive and easy system, and successfully hiding system-level concerns from the developer. Earlier user interfaces (UI) used to be completely XML, which made shifting from Android to iOS very difficult for developers. ... Flutter: Flutter provides the user with the functionality of building the app with both Android and iOS, with fewer costs, time, and efforts. This mainly means going inside our build system and making it issue the metrics we need for this analysis. React Native: It supports Android 4.0.3+ versions and iOS 8+. Over a million developers have joined DZone. The BuildPerfType enum member contains all the required information to generate a project for that specification, including potential custom arguments to kotlinc, dependencies (including, Kotlin stdlib, and Kapt, etc. For the project morphology-related data, e.g. On average, there are 27 files per project (i.e., the average total files across all 354 projects in the 13 build performance types). Trivial examples are not enough, as they often do not reflect real world conditions. This analysis was confined to somewhat small projects (between 1 and 500 files with an average file size of 27) due to the nature of our sampling space. However, our 13 options are still only a subset of what exists out there. We already implemented a flexible plugin system in the code generation to support custom post-processing, so adding the necessary controls to facilitate these new variants was easy. Subscribe to our newsletter to keep up with the latest innovations from Uber Engineering. Kotlin developers can efficiently work on the local environmental factors such as JS for the internet, Swift, and XCode for iOS, Android Studio. React Native interacts with the targeted (native) components for iOS or Android and renders code to native APIs directly and independently. … 4. This includes surfaces like data class copy()/hashCode()/equals()/toString() functions and destructuring component methods (though this language feature is only useful to Kotlin consumers). Performance. This can involve inferred return types, lambdas, member references, and generics. Kotlin shares many similarities with Swift, which is the programming language for iOS. Flutter: It supports Android Jelly Bean, v16, 4.1.x+ versions and iOS 8+. They are less verbose, easy to read, and comfortable to work with. Kotlin generates very similar bytecode to Java, so the performance of Kotlin code is in most cases the same as the performance of the equivalent Java code. Gradle supports multiple popular languages and technologies. Buck’s multi-thread build was turned off. 4. Although we have a metric that tells us the percentage of Java files present in the project, it is tightly coupled to the size of the project; in other words, as the percentage of Java changes, so does the size of the project. It’s developed by JetBrains who are currently working to bring Kotlin to embedded systems and iOS as well, potentially making it a one-stop language for all application areas. The wide set of features that Kotlin offers leaves us wanting to improve this analysis even further in order to account for situations such as: Smart casting: We don’t need smart casting in our generated model projects and so it was not covered in our analysis. Flutter vs Kotlin Performance. If Kotlin is used for Android and iOS app development, cross-platform development between the platforms will become simpler. We had to agree on a format for the data before shipping it to the database. These projects, in turn, contain a Buck file with a custom genrule that invokes the code generator to generate the appropriate source files for the project. Java vs Kotlin – In Terms of Performance. Due to the functional and syntactical similarities between Kotlin and Swift, the approaches to application functionality can be very identical. At Uber, we strive to maintain a modern tech stack in all our applications. Compiler avoidance/caching mechanisms can vary significantly between build systems, so we decided not to index on it for this project. Once all data was collected, it was assembled into a single JSON file and committed to a separate Git repository. The Language Stack Then, all that the analysis script had to do was run a command, such as: Given our stack’s usage of Buck, we leverage OkBuck to wrap the Buck usage. This does not mean that apps on both platforms can share a common code, of course, since the languages and OS-specific libraries aren’t identical. It is the official Android build tool. Opinions expressed by DZone contributors are their own. Kotlin is 100% interoperable with Java and offers backward compatibility with Java and Android projects. Namely, support for generating. The way this data is indexed would directly impact our ability to build visualizations in Kibana, our front-end system. Tho Nguyen is a senior software engineer on Uber's Amsterdam Mobile Developer Experience team. The layer of … Kotlin Multiplatform for iOS Developers DRY (or Don't Repeat Yourself) is one of the foundational principles of programming, but repeating lots … It’s clear that Kotlin will no longer remain only a trend, but will soon become a standard for Android development. This may have implications on performance in the sense that Buck’s implementation may not be as heavily optimized as first-party tools. To give a better overview of the generated code, we’ve created a repository with sample code for each of the variants and details of the underlying tech stack. We measured project performance between Pure Kotlin with Kapt (pink) and pure Kotlin (blue) setups, on the left, and pure Java with Apt (brown) and pure Java (turquoise), on the right. We recommend you to try out XCode first before checking out the others. Introducing Base Web, Uber’s New Design System for Building Websites in... ETA Phone Home: How Uber Engineers an Efficient Route, Announcing Uber Engineering’s Open Source Site. number of files, the number of lines that are blank, comments, or code and the number of generated classes and interfaces, we used a mix of the Count Lines of Code (CLoC) CLI and regular expressions, an analysis that looks into the generated project source files and not its compiled bytecode. . Kotlin is known for generating byte-code which is identical to byte-code of Java. The most interesting insights are described below: Throughout the 129 experiments, both javac and kotlinc reported consistent times. While it is important to keep the project size small so no single project blocks a thread by taking too long to finish and the system can continue to be performant, it is not a concern when it comes to causing exponential growth for individual build times. To achieve this, we established the following conditions for our model structures: We were in a unique position to perform such a measurement because we generate our network API models and services for Android from Apache Thrift specifications. Thanks to Google for making Kotlin an official Android language, cross-platform development between iOS and Android has become a lot easier. During our build performance experiments, we ran all the code gen pieces separately so the only measured piece is the compilation step. The JavaScript target for Kotlin has a new Gradle DSL and an alpha version of the Kotlin/JS IR compiler back end. This does not necessarily mean that Kotlin or Java sources would be identical in implementation, just that they reflected functional parity for how we would potentially write it in that language (for example, Gson TypeAdapter vs. Moshi JsonAdapter). By attempting to isolate the build system from the analysis we could not evaluate the impact of certain features provided or designed for particular build system, e.g. Kotlin shares many similarities with Swift, which is the programming language for iOS. Kotlin is officially launched for Android development by Google. Now, with the help of Kotlin, the UI can be designed and the look of the app can be a hybrid of both Android and iOS. An IDE is an application that aids the development of applications. Kotlin native is not optimized for performance today. ABI jar support: This was added in Kotlin 1.2.70 and allows computation of the ABI of a given library to quickly determine if recompilation of consumers is needed. Having an open source data set of projects only increases the range of analysis and unveils better insights. The natural evolution of software development brings several changes to observed compilation times. By sharing our results and lessons learned, we hope that others can use it to inform their own decisions. The analysis aggregated the data in buckets based on the build performance matrix (Table 1). . We analyzed the data using ElasticSearch and Kibana. Once you’ve downloaded the materials, open the starter project in Xcode by double-clicking on the MeteoriteFinder.xcodeproj file, and then run the app by clicking on the triangle button, shown below:Since this is the first time running the app, the Kotlin/Native compiler, which is named Konan, will download itself. For the project morphology-related data, e.g. Having a more diverse representation in terms of project size is imperative for better analysis. The syntax of Swift doesn’t just resemble that of Kotlin: in small chunks of code there can be up to 77% string similarity. This project structure results in 1.4 million lines of code (LoC) across 354 different projects that we can compare. But the ‘Kotlin vs Java performance’ debate is ongoing. A platform is an ideal option for developing Android, Desktop, Web, and iOS applications. This conflates the life cycle of the view with the state of the controller, breaking the fundamental abstraction of MVC. Kotlin is backed by Android Studio and supports the extension function. Both Swift and Kotlin are interoperable with Java and Objective-C, which makes it possible to use them in new projects and in the maintenance of old ones.