Spring Framework

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

A fast dependency injector for Android and Java.

The official home of the Presto distributed SQL query engine for big data

Suite of tools for deploying and training deep learning models using the JVM. Highlights include model import for keras, tensorflow, and onnx/pytorch, a modular and tiny c++ library for running mat…

Admin UI for administration of spring boot applications

Resilience4j is a fault tolerance library designed for Java8 and functional programming

A simple expressive web framework for java. Spark has a kotlin DSL https://github.com/perwendel/spark-kotlin

Java DSL for easy testing of REST services

Simple OAuth library for Java

Non-Blocking Reactive Foundation for the JVM

OpenGrok is a fast and usable source code search and cross reference engine, written in Java

Decompiler from Java bytecode to Java, used in IntelliJ IDEA.

Awaitility is a small Java DSL for synchronizing asynchronous operations

Real-time transport layer for Java AI agents. Build once with @Agent — deliver over WebSocket, SSE, gRPC, MCP, A2A, AG-UI, or any transport. Works with Spring AI, LangChain4j, Google ADK, Embabel, …

Java annotation processor to create immutable objects and builders, for records too. Sweep boilerplate code under the rug!

Log analyser / visualiser for Java HotSpot JIT compiler. Inspect inlining decisions, hot methods, bytecode, and assembly. View results in the JavaFX user interface.

VisualVM is an All-in-One Java Troubleshooting Tool

Apache Curator

A VT-100 terminal emulator for the Android OS

An extremely easy way to perform background processing in Java. Backed by persistent storage. Open and free for commercial use.

Implementation of various string similarity and distance algorithms: Levenshtein, Jaro-winkler, n-Gram, Q-Gram, Jaccard index, Longest Common Subsequence edit distance, cosine similarity ...

MATURE: A set of Maven tools for dealing with Dockerfiles

Spring Boot starter module for gRPC framework.

Java (and original) version of Hamcrest

GS Collections has been migrated to the Eclipse Foundation, re-branded as Eclipse Collections. https://www.eclipse.org/collections/

A JSON Schema validation implementation in pure Java, which aims for correctness and performance, in that order

ZeroTurnaround ZIP Library

Simpler, better and faster Java bean mapping framework

SSE Stream Aggregator