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

ZXing ("Zebra Crossing") barcode scanning library for Java, Android

Apache Kafka - A distributed event streaming platform

Redisson - Valkey & Redis Java client. Real-Time Data Platform. Sync/Async/RxJava/Reactive API. Over 50 Valkey and Redis based Java objects and services: Set, Multimap, SortedSet, Map, List, Queue,…

FizzBuzz Enterprise Edition is a no-nonsense implementation of FizzBuzz made by serious businessmen for serious business purposes.

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

Vert.x is a tool-kit for building reactive applications on the JVM

🏗 Build container images for your Java applications.

Very spicy additions to the Java programming language.

A Java API for generating .java source files.

A barebones WebSocket client and server implementation written in 100% Java.

A collection of source code generators for Java.

Java Native Access

Distributed and fault-tolerant realtime computation: stream processing, continuous computation, distributed RPC, and more

Efficient reliable UDP unicast, UDP multicast, and IPC message transport

A damn simple library for building production-ready RESTful web services.

The modern Java bytecode editor

Runtime code generation for the Java virtual machine.

⚠️ Processing moved to processing/processing4 ⚠️

Asynchronous Http and WebSocket Client library for Java

JavaFX Material Design Library

configuration library for JVM languages using HOCON files

Java 1-25 Parser and Abstract Syntax Tree for Java with advanced analysis functionalities.

BTrace - a safe, dynamic tracing tool for the Java platform

Thumbnailator - a thumbnail generation library for Java

LWJGL is a Java library that enables cross-platform access to popular native APIs useful in the development of graphics (OpenGL, Vulkan, bgfx), audio (OpenAL, Opus), parallel computing (OpenCL, CUD…

Distributed Graph Database

MapDB provides concurrent Maps, Sets and Queues backed by disk storage or off-heap-memory. It is a fast and easy to use embedded Java database engine.

The missing bridge between Java and native C++