Tag Archives: Kotlin

Google at KotlinConf ‘23

Posted by Márton Braun, Developer Relations Engineer

As part of Google’s ongoing commitment to supporting the Kotlin language, we are really excited to be a gold level sponsor for KotlinConf again this year. Grace Kloba shared the story of Google’s investments in Kotlin within the keynote, which is recapped in this post. You’ll also find the list of talks by Google from the event’s schedule below, make sure you catch these on the live stream.

For a summary of all KotlinConf keynote announcements, read the blog post by JetBrains.

Kotlin for Android

Kotlin started gaining popularity in the Android community around 2016. We were also impressed with Kotlin’s concise syntax, modern features, and safety. In 2017, we announced official support for Kotlin on Android, and committed to its future by creating the Kotlin Foundation with JetBrains.

Since then we invested in Kotlin by adding support in Android Studio, teaching the language to developers, and going Kotlin-first with our libraries, documentation, and samples. We also built Kotlin Symbol Processing, an API that enables annotation processors to run up to twice as fast as previous solutions.

Today, Kotlin is the most popular language for Android development. Over 95% of the top 1000 Android apps use Kotlin, and over 50% of professional Android developers use Kotlin as their primary language (compared with 25% choosing the Java programming language).

Among professional Android developers using Kotlin, we saw a 96.9% positive satisfaction rate in our latest annual survey, which is 9-points higher than their Java counterparts.

As our final step in making Kotlin the single language for Android development, we’re excited to announce today that the Gradle Kotlin DSL is becoming the default build language for Android apps, starting in Android Studio Giraffe. Read the blog post to learn more.

Jetpack Compose

Since going Kotlin-first, all new Jetpack libraries are written in Kotlin. Jetpack Compose, our modern toolkit for building Android apps, is Kotlin-only. It makes extensive use of Kotlin’s language features, and its implementation is made possible by Kotlin’s rich compiler API, which allows us to generate state management logic for you.

Jetpack Compose is changing the way developers build apps. The team from Clue shared with us that their development speed increased up to 3x after rewriting their app in Compose. Over 23% of the top 1000 Android apps ship with Compose, more than double year over year.

There are many resources available to learn Compose. For existing Android developers looking to expand their knowledge, we’ve published the Jetpack Compose for Android Developers course. For beginners to programming, we recommend taking the Android Basics with Compose course to learn Kotlin, Android, and Compose.

Kotlin at Google

Kotlin became generally available for Android development within Google in 2019. Since then, most of our Android apps are being built with Kotlin. As an example of the benefits, when the Google Home team migrated to Kotlin they saw a 33% decrease in NullPointerExceptions, which greatly improved the end user experience.

However, Google’s interest in Kotlin does not stop at Android apps. More than 45% of our engineers who write Kotlin use it for server development. We have over 15 million lines of Kotlin code in Google’s source control system, and this has been doubling year over year.

To support this, we have a dedicated team building tools to integrate Kotlin into Google’s ecosystem. You can catch the Adopting Kotlin at Google scale session for more details.

We’re looking forward to the new compiler in Kotlin 2.0, which will be a major improvement for developer productivity. We have a dedicated team working with JetBrains on the compiler, and we’re working to incorporate it into our tooling, including Android Studio, KSP, and the Compose compiler. We’re also leveraging our large internal codebase of Kotlin code to verify the compatibility of the new compiler.

Multiplatform

Looking forward, we are experimenting with Kotlin Multiplatform. This includes the Google Workspace team, who have a prototype with the business logic of Google Docs running on iOS using Kotlin Multiplatform and Kotlin/Native. Check out the Kotlin Multiplatform in Google Workspace lightning talk to learn more.

As part of our explorations into Kotlin Multiplatform, we’ve also made contributions that will benefit the community:

  • We’ve ported a set of Jetpack libraries to multiplatform. This allows you to use tools and APIs you know and love from Android and apply them to multiplatform. 
  • We’ve contributed to the Kotlin/Native toolchain, improving its performance. 
  • We’ve been helping out with the Gradle plugin for Kotlin Multiplatform, to give you more control over each target platform while still sharing as much code as possible.

Kotlin Foundation

As a founding member of the Kotlin Foundation, we’re excited about the Foundation’s expansions announced at KotlinConf:

  • Inviting more companies to collaborate on the development and promotion of Kotlin through a membership program. 
  • Offering funding for individual authors of actively maintained, open source Kotlin Multiplatform libraries.

With these steps, we continue to foster a healthy ecosystem for the language, and ensure its future advancement.

Catch us at KotlinConf

We look forward to sharing more in our sessions at KotlinConf, which you can tune in to on the live stream. If you’re attending in person, you can also visit us at our booth to have a chat about Kotlin.

April 13 schedule
Adopting Kotlin at Google scale
Jeffrey van Gogh, John Pampuch

Spring + Kotlin = Modern + Reactive + Productive
Josh Long, James Ward

Kotlin Multiplatform in Google Workspace
Jason Parachoniak

Kotlin Multiplatform Conversions at Android Jetpack Scale
Dustin Lam, James Ward

Untangling Coroutine Testing
Márton Braun

Adventures building a Kotlin Multiplatform Benchmarking Library
Rahul Ravikumar

April 14 schedule
Tracing coroutines in the JVM
Tyson Henning

Preventing Data Races in Async Coroutines
Kevin Bierhoff

Avoiding common coroutines mistakes in Compose
Márton Braun

*Java is a trademark or registered trademark of Oracle and/or its affiliates.

Interview with Top Kotlin Contributors – Highlighting their Contributions to the Google Dev Library

Posted by Swathi Dharshna Subbaraj, Project Coordinator, Google Dev Library

In May 2017, Google recognized the potential of Kotlin in the mobile developer community and made it an official language for Android development. As a result, talented developers in the Kotlin community used this robust programming language to build inspiring tools and open-source projects. This can be seen in the Google Dev Library, where developers have contributed extensively.

This article will showcase some of our Kotlin Google Developer Experts (GDEs) who have made significant contributions to the Google Dev Library. We hope these projects will inspire and guide your development efforts.
 

Contributors in Spotlight :


Nicola Corti

Nicola contributed Detekt to Google Dev Library, which is a static code analysis tool for Kotlin projects that helps developers detect and report on issues related to security, style, and best practices. It can be used to identify potential vulnerabilities, enforce coding standards, and improve code quality.

How did you get started in Kotlin? Is there any particular project that inspired you?

I began working with Kotlin in its early days of 2015. Though the experience was rocky, the ability to code Android apps in Kotlin rather than Java was a game-changer. At the time, it was challenging to convince my colleagues to switch due to the Java-dominant community. However, the official announcement of Kotlin support at Google I/O 2017 was a defining moment for the language. I am grateful for the ongoing support and development of such a powerful and versatile language, as well as the dedicated community that supports it daily.

I am grateful for the ongoing support and development of such a powerful and versatile language, and the dedicated community that supports it daily. - Nicola Corti, GDE Kotlin 

What inspired you to inherit the Detekt project ?

Detekt, a static code analyzer tool, is not a creation of mine, but rather a project that I inherited from a friend who sought support in managing it. I have always been impressed by the capabilities of static code analyzers, particularly in terms of their ability to detect bugs and save developer time. At the time, the market for Kotlin static analyzers was relatively new, making Detekt a valuable addition to the toolkits of many Kotlin developers.

As a Kotlin GDE, what is the one piece of advice for someone who has just started as a Kotlin developer?

I highly recommend getting involved in the open-source community. My contributions to open-source projects have taught me invaluable skills and knowledge that I wouldn't have gained otherwise. Additionally, I have had the opportunity to connect with incredible contributors who have since become friends. Participating in open-source not only benefits yourself, but also the wider developer community.

John O'Reilly

John created the PeopleInSpace project, and shared it with Google Dev Library. The project utilizes the OpenNotify API to display information about people currently in space, such as their names, nationalities, and spacecraft. The focus of the project is more about demonstrating use of Kotlin Multiplatform.

How did you get started in Kotlin? Is there any particular project that inspired you?
In 2010, I began my career as an Android developer, utilizing Java as my primary programming language. As a Java backend developer for the previous decade, the transition was relatively seamless. However, it wasn't until the official announcement of Kotlin support at Google I/O 2017, that I fully realized the potential impact of this new programming language. Gradually, as my team and I started migrating to Kotlin, I came to appreciate how productive and expressive a language it was to use.

As my team and I started migrating to Kotlin, I came to appreciate how productive and expressive a language it was to use.  - John O'Reilly, GDE Kotlin

What inspired you to develop and open source the Peopleinspace project?

In 2018, I was introduced to Kotlin Multiplatform (KMP) and was immediately impressed by its practical and efficient approach to code sharing. At the time, there was still a lot of uncertainty and confusion surrounding KMP, and I saw a need for a simple, easy-to-understand sample project that could demonstrate the basics of KMP.

I had an existing open-source project, GalwayBus, which I initially used to experiment with KMP, Jetpack Compose and SwiftUI as they became available. However, this project had a significant amount of legacy code and was not ideal for showcasing the essentials of KMP.

In late 2019, I came across an article by Ken Kousen that included sample code using retrofit to retrieve a list of people in space. I realized that this could be the perfect foundation for the minimal project I had been envisioning. So, I created PeopleInSpace, a project designed to encapsulate the core elements of a KMP project, and provide a clear and concise demonstration of how the various components work together.

As a Kotlin GDE, what is the one piece of advice for someone who has just started as a Kotlin developer?

Kotlin is a powerful language that offers many advanced features; however, it is possible to be very productive when starting out without needing to use those, in many cases, there are simpler alternatives that can be used, and as you become more familiar with the language, you can gradually explore and implement the more advanced options.
Join the global community of Kotlin developers and share your open source projects or technical blogs on Dev Library. To contribute, submit your content here.

How to learn Kotlin: JetBrains, the company behind the Kotlin language, offers certificate courses and learning tools for developers and has an active user groups forum where developers get support with programming language-related issues.

Google Cloud & Kotlin GDE Kevin Davin helps others learn in the face of challenges

Posted by Kevin Hernandez, , Developer Relations Community Manager

Kevin Davin speaking at the SnowCamp Conference in 2019

Kevin Davin has always had a passion for learning and helping others learn, no matter their background or unique challenges they may face. He explains, “I want to learn something new every day, I want to help others learn, and I’m addicted to learning.” This mantra is evident in everything he does from giving talks at numerous conferences to helping people from underrepresented groups overcome imposter syndrome and even helping them become GDEs. In addition to learning, Kevin is also passionate about diversity and inclusion efforts, partly inspired by navigating the world with partial blindness.

Kevin has been a professional programmer for 10 years now and has been in the field of Computer Science for about 20 years. Through the years, he has emphasized the importance of learning how and where to learn. For example, while he learned a lot while he was studying at a university, he was able to learn just as much through his colleagues. In fact, it was through his colleagues that he picked up lessons in teamwork and the ability to learn from people with different points of view and experience. Since he was able to learn so much from those around him, Kevin also wanted to pay it forward and started volunteering at a school for people with disabilities. Guided by the Departmental Centers for People with Disabilities, the aim of the program is to teach coding languages and reintegrate students into a technical profession. During his time at this center, Kevin helped students practice what they learned and ultimately successfully transition into a new career.

During these experiences, Kevin was always involved in the developer community through open-source projects. It was through these projects that he learned about the GDE program and was connected to Google Developer advocates. Kevin was drawn to the GDE program because he wanted to share his knowledge with others and have direct access to Google in order to become an advocate on behalf of developers. In 2016, he discovered Kubernetes and helped his company at the time move to Google Cloud. He always felt like this model was the right solution and invested a lot of time to learn it and practice it. “Google Cloud is made for developers. It’s like a Lego set because you can take the parts you want and put it together,” he remarked.

The GDE program has given him access to the things he values most: being a part of a developer community, being an advocate for developers, helping people from all backgrounds feel included, and above all, an opportunity to learn something new every day. Kevin’s parting advice for hopeful GDEs is: “Even if you can’t reach the goal of being a GDE now, you can always get accepted in the future. Don’t be afraid to fail because without failure, you won’t learn anything.” With his involvement in the program, Kevin hopes to continue connecting with the developer community and learning while supporting diversity efforts.

Learn more about Kevin on Twitter & LinkedIn.

The Google Developer Experts (GDE) program is a global network of highly experienced technology experts, influencers, and thought leaders who actively support developers, companies, and tech communities by speaking at events and publishing content.

Celebrating 5 years of Kotlin on Android

Posted by Márton Braun, Developer Relations Engineer

Five years ago, at the 2017 Google I/O Keynote, we did something we had never done before: we announced official support for a new programming language to build Android apps with: Kotlin. It was great to see how excited the Android developer community was about this announcement.


Since then, JetBrains and Google have been collaborating around the development of Kotlin, and the Kotlin Foundation was co-founded by the two companies.

As highlighted in those initial I/O announcements, Kotlin is interoperable, mature, production-ready, and open source. It also has outstanding IDE support, as JetBrains develops both the language and its tooling.

Now, five years have passed since the original announcement. To celebrate the amazing language that now powers modern Android app development, we’re taking a quick look at the journey of Kotlin on Android. This post includes quotes from a handful of people who were involved in making Kotlin on Android a success, who are joining us for this celebration.

Early years

The Kotlin adoption story started before official support from Google, within the Android developer community. The excitement in the community was one of the main reasons to invest in official support.
“The decision by Google to add support for Kotlin, I think we underestimate how wild of a notion that was at the time. The odds of another company that size making a similar decision based on community support and enthusiasm is very low.“ (Christina Lee, Android engineer at Pinterest, Kotlin and Android GDE)

After the 2017 announcement, Android Studio started shipping with built-in support for Kotlin. Lots of documentation and samples were updated to use Kotlin.

In 2018, we launched the Android KTX libraries, which provide Kotlin-friendly extensions wrapping the APIs of the Android framework and several AndroidX libraries. Tooling improved further, too, with Kotlin-specific live templates, lint checks, and optimizations in R8 and ART. The reference documentation for Android was also published in Kotlin for the first time.


Going Kotlin-first

At Google I/O 2019, we committed to Kotlin-first Android development, further increasing our investments in the language.
“If you look at a Kotlin new users graph, you immediately notice the two most significant spikes – one in May 2017 and another in May 2019. We have an inside joke about it: ‘Marketing a programming language is easy. All you have to do is make the largest operating system in the world call it an official language during the annual keynote’” (Egor Tolstoy, Kotlin Product Lead at JetBrains)

Being Kotlin-first means that we now design our documentation, samples, training content, new libraries and tools for the Kotlin language first, while still supporting users of the Java programming language.

”Now when we want to start a Jetpack Library, we are writing it in Kotlin unless we have a very, very, very good reason not to do that. It’s clear that Kotlin is the first-class language.” (Yigit Boyar, early proponent of Kotlin within Google, currently leading the development of a handful of Jetpack libraries)


Some examples of Kotlin-first Jetpack libraries are Paging 3 and DataStore, which are both powered by coroutines and Flows for asynchronous operations.


Jetpack Compose, Android’s modern UI toolkit is our greatest commitment to Kotlin so far, as it’s Kotlin-only. It’s powered by a Kotlin compiler plugin, and it makes extensive use of advanced language features like coroutines, top-level functions, and trailing lambdas.

“Kotlin is here to stay and Compose is our bet for the future. Right now, for developers that are starting to learn Android, we’re already recommending the Android Basics with Compose course.” (Florina Muntenescu, Jetpack Compose developer relations lead)


Kotlin beyond Android

Even though Kotlin is a great fit for Android, it’s a general-purpose language and not solely for use on Android. For teams within Google, Kotlin is now generally available to use for both Android and server-side projects. Thousands of Google engineers are writing Kotlin code, and our internal codebase contains more than 8.5 million lines of Kotlin code to date. This number has been increasing rapidly as well, doubling year over year.
“We’ve been working to bring Kotlin to Google engineers for the last few years by adding Kotlin support to all the tools they use. This includes the build system, static analysis tools, libraries and APIs. We’ve talked a lot about encouraging developers to use Kotlin for Android app development, and we strongly encourage using Kotlin for server-side development as well.” (Kevin Bierhoff, lead of the Kotlin at Google team, which supports Google engineers writing Kotlin code)

gRPC Kotlin and Kotlin for protocol buffers are examples of Kotlin projects Google uses both in Android apps and on servers that have been open sourced and are now receiving community adoption and contributions. Kotlin is also supported on Google Cloud.


Collaboration with JetBrains

There is close collaboration between JetBrains and Google around the development of Kotlin. The Kotlin Foundation was co-founded by the two companies, and it ensures that the language and ecosystem age well.

Google engineers have also been working on improving the compiler and on creating important tooling for the language.
“My team is helping JetBrains with rewriting the Kotlin compiler right now, and we also work on Kotlin Symbol Processing, which is the first compiler-related Kotlin project that’s been completely done at Google. We work more closely with JetBrains than some other parts of Google." (Jeffrey van Gogh, member of the Kotlin Foundation, lead of the Kotlin engineering team at Google)

JetBrains and Google also coordinate new releases of the language and the accompanying tooling so that developers are able to use the latest releases as smoothly as possible.
“The collaboration gets stronger over time, and I’m really excited to see its impact on Kotlin’s future. Our coordinated pre-release checks are getting better and better." (Liliia Abdulina, Kotlin QA team lead at JetBrains)


Learn more and share your own stories

You can read more stories about Kotlin from our interviewees in the accompanying Medium post. We’d also love to hear your stories of learning and adopting Kotlin for Android development! Share them on social media using the hashtag #Hi5KotlinOnAndroid!

Finally, let’s appreciate these kind words about Kotlin’s accomplishments to conclude our story.

“Technology can really change people's lives and it can really make people happier at work. We normally focus on ‘there's null safety’ or ‘there's type inference’ or all these other technical parts. But when you take a step back, there's a whole story in there about all of the people who had their passion for coding ignited or reignited because Kotlin is such a wonderful language. It's just so impressive that the team is able to do what they're able to do and that the community is as good as it is." (Christina Lee, Android engineer at Pinterest, GDE for Android and Kotlin)

Have a nice Kotlin on Android!

*Java is a trademark or registered trademark of Oracle and/or its affiliates.

Discontinuing Kotlin synthetics for views

Posted by Márton Braun, Developer Relations Engineer


ALT TEXT GOES HERE 

Synthetic properties to access views were created as a way to eliminate the common boilerplate of findViewById calls. These synthetics are provided by JetBrains in the Kotlin Android Extensions Gradle plugin (not to be confused with Android KTX).

In November 2020, we announced that this plugin has been deprecated in favor of better solutions, and we recommended removing the plugin from your projects. We know many developers still depend on this plugin’s features, and we’ve extended the support timeframe so you have more time to complete your migrations.

We are now setting a deadline for these migrations: the plugin will be removed in Kotlin 1.8, which is expected to be released by the end of 2022. At that time, you won’t be able to update your project to newer Kotlin versions if it still depends on the Kotlin Android Extensions plugin. This means that now is the time to perform the necessary migrations in your projects.

Instead of synthetics, we recommend using View Binding, which generates type-safe binding classes from XML layout files. These bindings provide convenient access to view references and they work safely for layouts with multiple configurations. See the migration guide for detailed instructions on how to adopt View Binding. If you encounter any issues, you can report a bug on the Issue Tracker.

When building new features, consider using Jetpack Compose, Android's modern UI toolkit. Layouts built with Compose are declarative Kotlin code, eliminating the need to work with view references.

Another feature included in the plugin is Parcelize, which helps you create parcelable classes. Parcelize is now available in the standalone kotlin-parcelize plugin with unchanged functionality. To get up and running with the new plugin, check out the Parcelize documentation page.

If you’re still using the Kotlin Android Extensions Gradle plugin, kick off your migration in time so that you can keep upgrading to new Kotlin releases in the future. This will enable you to use the latest language features and take advantage of tooling and compiler improvements.

Android Basics and Training Update

Posted by Dan Galpin, Developer Relations Engineer

Android robot on a pretend video call

In October of 2021 we released the final unit of Android Basics in Kotlin, our free, self-paced programming course that makes Android development accessible to everyone. It teaches people with no programming experience how to build Android apps. Along the way, students learn the fundamentals of programming and the basics of the Kotlin programming language.

In response to feedback from educators and learners, we've continued to iterate on our course material, adding projects that allow you to apply learnings along with new topics that can prepare students for more advanced material.

A focus on basics

With these updates, Android Basics in Kotlin now covers the key material covered in Android Kotlin Fundamentals, so we will be sunsetting the latter course. More advanced learners are encouraged to work through the Basics material, skipping sections that they are familiar with and moving straight to quizzes. Focusing on basics means that intermediate and advanced learners that might be missing a key concept will have what they need to succeed with this material. This also allows our team to focus on making sure our courseware continues to represent our most recent guidance. In addition to courseware, we're continuing to provide codelabs, code samples, documentation, and video content to serve learners at all levels.

What's next?

Our team is hard at work on the next course that will teach people how to program Android applications using Jetpack Compose. We're looking forward to teaching Android’s modern toolkit for building native UI because of all the ways that it simplifies and accelerates Android UI development.

What to do now

Taking the current course will teach you the fundamentals of app development, serving as a great starting point should you want to explore the existing Jetpack Compose Learning Pathway, or jump into the upcoming Android Basics with Compose course. You'll have a foundation that you can build on as you continue to explore the world of Android development. Both versions of Android Basics are planned to coexist, giving the option of learning Android with either UI toolkit.

Whether you’ve never built an app before but want to learn how, or just want to brush up on some of our latest best practices, check out the Android Basics in Kotlin course.

Announcing Kotlin support for protocol buffers

Posted by Deanna Garcia and Louis Wasserman - Software Developers, and Developer Advocate, James Ward

Google’s commitment to Kotlin

At Google, we’re investing deeply in the Kotlin language and ecosystem. Android development is now Kotlin first, our engineering teams work on language evolution through the Kotlin Foundation, and inside of Google we’re using Kotlin more and more to build our backend services. We love Kotlin for its expressiveness, safety, simple async support through coroutines, and easy bidirectional interoperability with the Java programming language.

Kotlin for protocol buffers

Last year, we open sourced Kotlin support for gRPC, the open source Remote Procedure Call (RPC) framework that powers thousands of microservices at Google. We’re excited to deepen our investment in the Kotlin language with official support for Kotlin in the open source Protocol Buffers project (a.k.a. “protos”), Google’s platform-neutral, high-performance data interchange format. From a proto definition, you can use the new built-in Kotlin support in the proto compiler to generate idiomatic Kotlin Domain Specific Languages (DSLs).

For example, here’s a simple protocol buffer message representing a series of dice rolls: 

message DiceSeries {
  message DiceRoll {
    int32 value = 1;      // value of this roll, e.g. 2..12
    string nickname = 2;  // string nickname, e.g. "snake eyes"
  }

  repeated DiceRoll rolls = 1;
}

In the Java language, constructing a series of dice rolls might look like this: 

DiceSeries series = DiceSeries.newBuilder()
    .addRoll(DiceRoll.newBuilder()
        .setValue(5))
    .addRoll(DiceRoll.newBuilder()
        .setValue(20)
        .setNickname("critical hit"))
    .build()

With this release, protos offer an expressive set of DSL factory methods that make this code elegant and idiomatic in Kotlin. Here is the equivalent dice roll code written using the new Kotlin proto bindings: 

val series = diceSeries {
  rolls = listOf(
    diceRoll { value = 5 },
    diceRoll {
      value = 20
      nickname = "critical hit"
    }
  )
}

The Kotlin version uses Kotlin type-safe builders, which makes it concise and removes the need to explicitly call a build method. Note that this works with both the proto compiler’s standard and "proto lite" modes, the latter generating smaller, higher performance classes which are more suitable for Android.

Note: Since protos use the get prefix for their fields and Kotlin recognizes that as a property, reading from a proto already works smoothly from Kotlin as if the proto were a data class. 

val totalRolls = series.rolls.map { it.value }.sum() // 5 + 20 = 25

Kotlin Protos and gRPC Kotlin

The new Kotlin Protos work great with gRPC Kotlin providing a concise syntax for messages and services. Let's walk through a basic sample.

Here is a basic "Greeter" gRPC service proto: 

service Greeter {
  rpc SayHello (HelloRequest) returns (HelloReply) {}
}

message HelloRequest {
  string name = 1;
}

message HelloReply {
  string message = 1;
}

Check out the full example proto source.

The non-blocking server can be implemented concisely, taking advantage of the Kotlin proto builders: 

class HelloWorldService : GreeterCoroutineImplBase() {
  override suspend fun sayHello(request: HelloRequest) = helloReply {
    message = "hello, ${request.name}"
  }
}

Check out the full example server source.

The non-blocking client also can take advantage of the type-safe Kotlin builders with concise syntax: 

val stub = GreeterCoroutineStub(channel)
val request = helloRequest { name = "world" }
val response = stub.sayHello(request)
println("Received: ${response.message}")

Check out the full example client source.

Those code examples really illustrate how concise the syntax is, which means less boilerplate to write and less for our brains to parse as we try to read the code. What isn't evident in these examples is how nice the experience is when writing high-performance RPC code. Thanks to static typing and the type-safe builders, you can easily code-complete your way through code that is "correct" in-that the types / properties are consistent with the protos.

The protobuf compiler (protoc) now has built-in support for generating Kotlin code. A bit of configuration is needed to tell your build tool (Maven, Gradle, etc) to do that. For Gradle builds it looks like: 

protobuf {
    // omitted protoc and plugins config
    generateProtoTasks {
        all().forEach {
            // omitted plugins config
            it.builtins {
                id("kotlin")
            }
        }
    }
}

Check out the full example Gradle build.

Give the complete gRPC Kotlin example a spin and also explore other aspects like the Android client and native client (built with GraalVM Native Image) which both use the lite protos. For an example Maven project check out the grpc-hello-world-mvn sample.

For examples that can be deployed with a couple clicks on Google Cloud Run (a fully managed serverless platform) check out: grpc-hello-world-gradle, grpc-hello-world-streaming (server push), or grpc-hello-world-bidi-streaming (bi-directional streaming).

Learn More

To learn more about Kotlin protos check out these docs:

Let us know how it goes and if you have any Kotlin proto issues by filing them within the official protobuf project.

Additional thanks to Adam Cozzette, Brent Shaffer, David Jones, David Winer, Jeff Grimes, John Pampuch, and Kevin Bierhoff for their contributions to this release!

Accelerated Kotlin build times with Kotlin Symbol Processing 1.0

Posted by Ting-Yuan Huang, Software Engineer and Jiaxiang Chen, Software Engineer

Accelerated Kotlin build times with Kotlin Symbol Processing 1.0 image

Kotlin Symbol Processing (KSP), our new tool for building lightweight compiler plugins in Kotlin, is now stable! KSP offers similar functionality to the Kotlin Annotation Processing Tool (KAPT), however it’s up to 2x faster, offers direct access to Kotlin language constructs, and offers support for multiplatform targets.

Over the past few months, KSP has gone through 32 releases with over 162 bugs reported from the community and fixed by our team. If you were waiting to adopt it, now is the time to check it out.

Why we built KSP

On the Android team, we regularly ask developers: what are your biggest frustrations with writing apps today? One of the top issues that comes up repeatedly is build speed. Over the years we’ve been making steady improvements to the Android build toolchain, and today we’re excited to add to those improvements with KSP. KSP is the next generation of annotation processing in Kotlin: it will dramatically improve build speed for Kotlin developers, and unlike KAPT, it offers support for Kotlin/Native and Kotlin/JS.

Why is KSP faster?

The Kotlin Annotation Processing Tool (KAPT) works with Java’s annotation processing infrastructure to make most Java language annotation processors work in Kotlin out of the box. To do this, KAPT compiles Kotlin code into Java stubs that retain information that Java annotation processors care about. Creating these stubs is costly though, and means the compiler must resolve all the symbols in your program multiple times (once to generate stubs, and then again to do the actual compilation).

KSP moves away from the stub generation model by working as a Kotlin compiler plugin — it allows annotation processors to read and analyze source programs and resources directly in Kotlin instead of requiring you to depend on the Java annotation processing infrastructure. This both dramatically improves build speed (up to 2x faster for Room's Kotlin test app) and means that KSP can be used for non-Android and non-JVM environments like Kotlin/Native and Kotlin/JS.

How to get started

To start using KSP, download the KSP playground project from GitHub, which shows how to use KSP both as an annotation processor and as a consuming app/library:

  • Annotation processor: A toy test-processor library that implements the builder pattern as a KSP processor
  • Consuming library: A workload directory that shows how to use the builder processor in a real-world Kotlin project

If you’re an app developer, check out the list of supported libraries and the quickstart guide for moving a module over from KAPT to KSP.

Using Moshi or Room with KSP

If you’re using Moshi or Room in your project, you can already try out KSP by making a quick fix to your module’s build file. For example, to use the KSP version of Room in a Gradle module you can simply replace the KAPT plugin with KSP and swap out the KSP dependency: 

apply plugin: 'com.google.devtools.ksp'

dependencies {
  ...
  implementation "androidx.room:room-runtime:$room_version"
  kapt "androidx.room:room-compiler:$room_version"
  ksp "androidx.room:room-compiler:$room_version"

}

Check out the Room release notes for more info.

Conclusion

With the 1.0 release of KSP you will start to see improved build times for your Kotlin projects as you migrate away from libraries based on KAPT. We have also updated a number of Android specific libraries which are ready for you to try today and offer significant performance improvements.

Android @ Google I/O: 3 things to know in Modern Android Development

Posted by The Modern Android Development Team

This year’s Google I/O brought lots of updates for Modern Android Development. Here are the top 3 things you should know:

#1: Lots of new Jetpack library releases!

In recent months, several Jetpack libraries reached stable, beta or were just launched in alpha. Here are some the highlights:

To find out more about what’s new, check out the What’s new in Jetpack, What’s new in Compose and for a deep dive into Macrobenchmark: Measuring Jank and Startup with Macrobenchmark.

#2: Inspectors in Android Studio

Debugging your application becomes easier with all the inspectors provided by Android Studio Arctic Fox: for background work, like understanding what’s the status of your WorkManager workers, use Background Task Inspector; for UI use Layout Inspector, for both Android Views and Compose; for database debugging use Database Inspector.

To see the inspectors in action, check out What’s new in Android development tools.

#3: New features in Kotlin

We keep improving Kotlin on Android at all levels, from tools to APIs, and giving you different ways to learn. Kotlin Symbol Processing (KSP), now in alpha, provides a simplified compiler plugin API that can run up to 2 times faster than KAPT. Together with JetBrains, we’re addressing performance issues in the IDE and we’re seeing up to 20x faster auto-import suggestions. We added StateFlow support to DataBinding and new APIs for observing Flows in the UI without DataBinding. To learn about all the improvements we’ve made for Kotlin, check out the State of Kotlin on Android talk:

You can find all of this year’s Google I/O talks covering Modern Android Development in this playlist:

A conversation with Hebe He, a developer from Guangzhou

Posted by Brian Shen, Program Manager, Google Developers

Google Developer Groups are one of the largest community networks of developers in the world. Every group has an organizer that helps curate events based on the interests of their local developer community.

As we continue to explore how different Google Developer Groups build their communities, we interviewed Hebe He, an organizer of Google Developer Group Guangzhou in China. Learn more about how she is building the developer scene in China, thinking up new events for her community, and more below.

Hebe He, an organizer of Google Developer Group Guangzhou in China.

Hebe He, an organizer of Google Developer Group Guangzhou in China.

Tell us about yourself.

I am Hebe from China and I'm a native of Guangzhou. I'm the organizer of GDG Guangzhou, as well as an ambassador for Women Techmakers (WTM). I work at one of China's new electric-vehicle brands, where I'm responsible for the intelligent business operation of the Internet of Vehicles. I'm relatively outgoing and active, so I really like to deal with different people, whether it's at work or in other activities.

How did you learn about Google Developer Groups?

In 2014, I participated in GDG Guangzhou DevFest for the first time by coincidence and met the founder of GDG Guangzhou. Afterward, I joined the founder's company and volunteered at many GDG programs. In 2017, I officially became an organizer after the existing organizers recognized my ability and desire to contribute more to the GDG Guangzhou community.

Tell us more about Guangzhou and the developer community there.

Our community members are talented, passionate, and amazing. I see all kinds of possibilities in them. They're always excited for every event we hold, keep a fanatical attitude toward Google's technological innovation, and are particularly interested in Android, Kotlin, and Flutter.

What are events like in your community?

We highly value feedback from event participants, who are interested in a wide range of topics. For this reason, we generally use 15% of every event to cover non-technical topics, such as entrepreneurship, business management, and careers. For more comprehensive activities, such as DevFest, we increase the amount of non-technical content to roughly 30%.

What is your Google Developer Group focused on right now?

We devote most of our energy to improving the quality of activities. We try to add more elements to the event to strengthen the interaction of participants in hopes of improving the feedback mechanism and gaining more valuable suggestions for future event optimization. We also try to improve the quality of guests and themes, and pay more attention to event details, such as event announcements, registration, and check-in.

What’s your favorite community memory from a Google Developer Group event?

The memory that touches me the most is the construction of WTM Guangzhou. From the first event with only 80 developers to the audience of more than 500 people in recent years, it represents the recognition of, and support for, our events. There are many people who come to participate every year; some are actively encouraging their friends to participate and others are even urging us to hold events. They feel honored to be invited to our events and their enthusiasm endured during the pandemic.

What's next for you and your Google Developer Group?

There's still lots of room to grow in our community. We hope that we can continue to develop a Google Developer Group that reflects the best of Guangzhou. We also hope to find better ways to accumulate the experience shared by speakers and the value of community users.

If you want to grow your career and coding knowledge with people like Hebe He, join a Google Developer Group near you.