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

Netty project - an event-driven asynchronous network application framework

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

Hystrix is a latency and fault tolerance library designed to isolate points of access to remote systems, services and 3rd party libraries, stop cascading failure and enable resilience in complex di…

A Java serialization/deserialization library to convert Java Objects into JSON and back

JDK main-line development https://openjdk.org/projects/jdk

光 HikariCP・A solid, high-performance, JDBC connection pool at last.

A high performance caching library for Java

Quarkus: Supersonic Subatomic Java.

Most popular Mocking framework for unit tests written in Java

The ZAP by Checkmarx Core project

Style and Grammar Checker for 25+ Languages

🏗 Build container images for your Java applications.

Zuul is a gateway service that provides dynamic routing, monitoring, resiliency, security, and more.

Java JWT: JSON Web Token for Java and Android

The Clojure programming language

Feign makes writing java http clients easier

Java JsonPath implementation

Testcontainers is a Java library that supports JUnit tests, providing lightweight, throwaway instances of common databases, Selenium web browsers, or anything else that can run in a Docker container.

Java DSL for easy testing of REST services

Asynchronous Http and WebSocket Client library for Java

vʌvr (formerly called Javaslang) is a non-commercial, non-profit object-functional library that runs with Java 8+. It aims to reduce the lines of code and increase code quality.

Automated JSON API documentation for API's built with Spring

Advanced Java Redis client for thread-safe sync, async, and reactive usage. Supports Cluster, Sentinel, Pipelining, and codecs.

Simple OAuth library for Java

This is the new home of the original DDD Sample app (previously hosted at sf.net)..

H2 is an embeddable RDBMS written in Java.

High performance non-blocking webserver

Apache Heron (Incubating) is a realtime, distributed, fault-tolerant stream processing engine from Twitter

The reliable, generic, fast and flexible logging framework for Java.