RxJava – Reactive Extensions for the JVM – a library for composing asynchronous and event-based programs using observable sequences for the Java VM.

A powerful 🚀 Android chart view / graph view library, supporting line- bar- pie- radar- bubble- and candlestick charts as well as scaling, panning and animations.

Render After Effects animations natively on Android and iOS, Web, and React Native

An image loading and caching library for Android focused on smooth scrolling

FASTJSON 2.0.x has been released, faster and more secure, recommend you upgrade.

Bind Android views and callbacks to fields and methods.

Event bus for Android and Java that simplifies communication between Activities, Fragments, Threads, Services, etc. Less code, better quality.

Desktop/Android/HTML5/iOS Java game development framework

a fast, scalable, multi-language and extensible build system

This project is deprecated and stale. The latest ExoPlayer code is available in https://github.com/androidx/media

GraalVM compiles Java applications into native executables that start instantly, scale fast, and use fewer compute resources 🚀

Implementation of ImageView for Android that supports zooming, by various touch gestures.

A fast dependency injector for Android and Java.

ANTLR (ANother Tool for Language Recognition) is a powerful parser generator for reading, processing, executing, or translating structured text or binary files.

Most popular Mocking framework for unit tests written in Java

Tink is a multi-language, cross-platform, open source library that provides cryptographic APIs that are secure, easy to use correctly, and hard(er) to misuse.

APM, (Application Performance Management) tool for large-scale distributed systems.

Very spicy additions to the Java programming language.

Stetho is a debug bridge for Android applications, enabling the powerful Chrome Developer Tools and much more.

The Most Powerful Swipe Layout!

Realm is a mobile database: a replacement for SQLite & ORMs

Fast Android Development. Easy maintainance.

A collection of source code generators for Java.

Paging indicator widgets compatible with the ViewPager from the Android Support Library and ActionBarSherlock.

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

Android filters based on OpenGL (idea from GPUImage for iOS)

Epoxy is an Android library for building complex screens in a RecyclerView

Flyway by Redgate • Database Migrations Made Easy.

A Material Design ViewPager easy to use library

Android library (AAR). Highly configurable, easily extendable deep zoom view for displaying huge images without loss of detail. Perfect for photo galleries, maps, building plans etc.