Java Kotlin

Open-source Java projects categorized as Kotlin

Top 23 Java Kotlin Projects

  • GitHub repo OkHttp

    Square’s meticulous HTTP client for the JVM, Android, and GraalVM.

    Project mention: Spring boot | | 2021-03-20

    There are 3rd party HTTP clients like Apache HttpClient and OkHttp ( and

  • GitHub repo Permission Dispatcher

    A declarative API to handle Android runtime permissions.

  • GitHub repo glide-transformations

    An Android transformation library providing a variety of image transformations for Glide.

  • GitHub repo android-classyshark

    Analyze any Android/Java based app or game

  • GitHub repo REST Assured

    Java DSL for easy testing of REST services

    Project mention: Contract-First Development Using RestAssured and OpenAPI | | 2021-04-09

    In this post, we will demonstrate how can OpenAPI be used in a RestAssured-based integration test to ensure that the API conforms to its specification.

  • GitHub repo dialogplus

    Advanced dialog solution for android

  • GitHub repo Micronaut

    Micronaut Application Framework

    Project mention: Jordan peeps how did you spend your weekend 🤔 | | 2021-04-12

    I need to to use Micronaut at work:

  • GitHub repo junit5

    ✅ The 5th major version of the programmer-friendly testing framework for Java and the JVM

    Project mention: How to detect all test classes in JUnit5 finish? | | 2021-01-16

    I was chasing similar problem, while I didn't find docs, and yet to try it, here is what I found so far. The idea is to use context closable store to be notified when things are done. Here is GitHub issue with an example: And here is some relevant PRs that were merged into JUnit5

  • GitHub repo Android Tips & Tricks

    :ballot_box_with_check: [Cheatsheet] Tips and tricks for Android Development

  • GitHub repo GmsCore

    Free implementation of Play Services

    Project mention: Virer Google de mon téléphone portable ? | | 2021-04-12
  • GitHub repo LWJGL

    LWJGL is a Java library that enables cross-platform access to popular native APIs useful in the development of graphics (OpenGL, Vulkan), audio (OpenAL), parallel computing (OpenCL, CUDA) and XR (OpenVR, LibOVR) applications.

    Project mention: Need help with planning a GUI project for my finals | | 2021-04-04

    Lightweight Java Game Library

  • GitHub repo AutoDispose

    Automatic binding+disposal of RxJava streams.

    Project mention: RxJava is better than kotlin coroutines? | | 2021-01-25

    I am biased because I don't consider calling compositeDisposable.clear() at the right places hard. Some places have created very elaborate measures to need to avoid that, so maybe I'm missing something.

  • GitHub repo requery

    requery - modern SQL based query & persistence for Java / Kotlin / Android

  • GitHub repo apollo-android

    :robot: A strongly-typed, caching GraphQL client for the JVM, Android and Kotlin multiplatform

  • GitHub repo JaCoCo

    :microscope: Java Code Coverage Library

  • GitHub repo FXGL

    Java / JavaFX / Kotlin Game Library (Engine)

    Project mention: What are some free programs for making small games? | | 2021-04-10

    Since your asking in r/javahelp , I believe you want to make a game in Java. The easiest way is to use a game engine and I can really recommend FXGL. You can find it here: together with information about how to use this library and a lot of example projects (from simple to advanced).

  • GitHub repo spotless

    Keep your code spotless

    Project mention: Is there any actively maintained Java library to format code? | | 2021-03-08
  • GitHub repo android-developer-roadmap

    Android Developer Roadmap - A complete roadmap to learn Android App Development

    Project mention: Newbie tips. | | 2021-03-06

    I’d say take a look at the road map here

  • GitHub repo Shortbread

    Android library that creates app shortcuts from annotations

  • GitHub repo spring-fu

    KoFu and JaFu configuration DSLs for Spring Boot

    Project mention: The Modern Java Platform | | 2021-03-16

    There's a next stage after annotations. The current thinking is to replace annotations with function calls. It makes more sense if you use Kotlin because Java is a bit verbose when you do this and in Kotlin you get to create nice DSLs. This cuts down on use of reflection and AOP magic that spring relies on and also enables native compilation. It also makes it easier to debug and it makes it much easier to understand what is going on at the price of surprisingly little verbosity. Kofu and Jafu are basically still experimental but work quite nicely

    Another trend is native compilation. Spring native just went into beta (uses the Graal compiler). That still relies on reflection but they re-engineered the internals to be more native friendly.

    Spring Boot basically added the notion of autoconfiguring libraries that simply by being on the classpath self configure in a sane way. It's one of those things that makes the experience a bit more ruby on rails like. Stuff just works with minimal coding and you customise it as needed (or not, which is perfectly valid).

    Compared to XML configuration, Spring has come a long way. Separating code and configuration is still a good idea with Spring but indeed not strictly enforced. @Configuration classes can take the place of XML and if you use the bean dsl, that's basically the equivalent of using XML. Only it's type checked at compile time and a bit more readable.

  • GitHub repo Anvil

    Minimal UI library for Android inspired by React

  • GitHub repo Jooby

    The modular web framework for Java and Kotlin

    Project mention: What would you use to start a new HTTP + SSR project with Java today? | | 2021-03-28


  • GitHub repo Ebean ORM

    Ebean ORM

    Project mention: Stop Using JPA/Hibernate | | 2021-04-11

    I wouldn't call it micro, but is pretty nice.

NOTE: The open source projects on this list are ordered by number of github stars. The number of mentions indicates repo mentiontions in the last 12 Months or since we started tracking (Dec 2020). The latest post mention was on 2021-04-12.


What are some of the best open-source Kotlin projects in Java? This list will help you:

Project Stars
1 OkHttp 39,729
2 Permission Dispatcher 10,529
3 glide-transformations 9,261
4 android-classyshark 6,737
5 REST Assured 5,269
6 dialogplus 4,890
7 Micronaut 4,841
8 junit5 4,526
9 Android Tips & Tricks 4,405
10 GmsCore 3,519
11 LWJGL 3,149
12 AutoDispose 3,104
13 requery 3,050
14 apollo-android 2,699
15 JaCoCo 2,632
16 FXGL 1,876
17 spotless 1,854
18 android-developer-roadmap 1,819
19 Shortbread 1,789
20 spring-fu 1,470
21 Anvil 1,418
22 Jooby 1,316
23 Ebean ORM 1,178