ReactiveX / RxJava
RxJava – Reactive Extensions for the JVM – a library for composing asynchronous and event-based programs using observable sequences for the Java VM.
ReactiveX / RxJava
lysine-dev / retrofit
A type-safe HTTP client for Android and the JVM
alibaba / arthas
Alibaba Java Diagnostic Tool Arthas/Alibaba Java诊断利器Arthas
openjdk / jdk
JDK main-line development https://openjdk.org/projects/jdk
itwanger / toBeBetterJavaer
一份通俗易懂、风趣幽默的Java学习指南，内容涵盖Java基础、Java并发编程、Java虚拟机、Java企业级开发、Java面试等核心知识点。学Java，就认准二哥的Java进阶之路😄
eclipse-vertx / vert.x
Vert.x is a tool-kit for building reactive applications on the JVM
deeplearning4j / deeplearning4j
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 math code and a java based math library on top of the core c++ library. Also includes samediff: a pytorch/tensorflow like library for running deep learn...
langchain4j / langchain4j
LangChain4j is an idiomatic, open-source Java library for building LLM-powered applications on the JVM. It offers a unified API over popular LLM providers and vector stores, and makes implementing tool calling (including MCP support), agents and RAG easy. It integrates seamlessly with enterprise Java frameworks like Quarkus and Spring Boot.
testcontainers / testcontainers-java
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.
dropwizard / metrics
:chart_with_upwards_trend: Capturing JVM- and application-level metrics. So you know what's going on.
Col-E / Recaf
The modern Java bytecode editor
junit-team / junit-framework
✅ The programmer-friendly testing framework for Java and the JVM
AsyncHttpClient / async-http-client
Asynchronous, non-blocking HTTP & WebSocket client for the JVM
lightbend / config
configuration library for JVM languages using HOCON files
btraceio / btrace
Production-safe dynamic tracing and diagnostics for Java applications—attach to live JVMs with no restart or recompilation.
reactor / reactor-core
Non-Blocking Reactive Foundation for the JVM
SPLWare / esProc
esProc SPL is a JVM-based programming language designed for structured data computation, serving as both a data analysis tool and an embedded computing engine.
objectbox / objectbox-java
Database for Android and JVM - first and fast, lightweight on-device vector database
Atmosphere / atmosphere
Portable AI agent runtime for the JVM. One @Agent class runs on Spring AI, LangChain4j, Anthropic, or 9 more behind one SPI. Token streaming, tool calls, human approvals, and governance over WebSocket, SSE, gRPC, or WebTransport/HTTP3. Speaks MCP, A2A, and AG-UI.
apache / logging-log4j2
Apache Log4j is a versatile, feature-rich, efficient logging API and backend for Java.
AxonIQ / AxonFramework
Framework for Evolutionary Message-Driven Microservices on the JVM
eclipse-openj9 / openj9
Eclipse OpenJ9: A Java Virtual Machine for OpenJDK that's optimized for small footprint, fast start-up, and high throughput. Builds on Eclipse OMR (https://github.com/eclipse/omr) and combines with the Extensions for OpenJDK for OpenJ9 repo.
konsoletyper / teavm
Compiles Java bytecode to JavaScript, WebAssembly and C
assertj / assertj
Fluent testing assertions for Java and the JVM
cucumber / cucumber-jvm
Cucumber for the JVM
mongodb / mongo-java-driver
The official MongoDB drivers for Java, Kotlin, and Scala
apache / logging-flume
Apache Flume is a distributed, reliable, and available service for efficiently collecting, aggregating, and moving large amounts of log-like data
prometheus / client_java
Prometheus instrumentation library for JVM applications
jdbi / jdbi
The Jdbi library provides convenient, idiomatic access to relational databases in Java and other JVM technologies such as Kotlin, Clojure or Scala.
testng-team / testng
TestNG testing framework
openjdk / loom
https://openjdk.org/projects/loom
Discord4J / Discord4J
Discord4J is a fast, powerful, unopinionated, reactive library to enable quick and easy development of Discord bots for Java, Kotlin, and other JVM languages using the official Discord Bot API.
codenameone / CodenameOne
Open-source framework for native apps from one Java codebase, with a custom-rendered UI you control across iOS, Android, desktop, web, and watches.
hcoles / pitest
State of the art mutation testing system for the JVM
datafaker-net / datafaker
Generating fake data for the JVM (Java, Kotlin, Groovy) has never been easier!
babyfish-ct / jimmer
The most advanced ORM of JVM, for both java & kotlin
hawtio / hawtio
Hawtio web console helps you manage your JVM stuff and stay cool!
microsoft / gctoolkit
Tool for parsing GC logs
CodeIntelligenceTesting / jazzer
Coverage-guided, in-process fuzzing for the JVM
sksamuel / scrimage
JVM - Java, Kotlin, Scala image processing library
jspecify / jspecify
An artifact of fully-specified annotations to power static-analysis checks, beginning with nullness analysis.
ngs-doo / dsl-json
High performance JVM JSON library
MobiVM / robovm
Ahead of time compiler for JVM bytecode targetting iOS, Mac OSX and Linux
mirkosertic / Bytecoder
Framework to interpret and transpile JVM bytecode to JavaScript, OpenCL or WebAssembly.
smallrye / smallrye-mutiny
An Intuitive Event-Driven Reactive Programming Library for Java
lucee / Lucee
Lucee is a high-performance, open-source CFML server written in Java. Supporting JDBC, Caching, Parallelism, HTTP, ORM, REST, S3 and dynamic Java integration, Lucee is great for developers aiming to build fast, scalable applications, delivering faster startup, rapid compilation and better runtime performance.
SpaiR / imgui-java
JNI based binding for Dear ImGui
PowerNukkitX / PowerNukkitX
Open-source, feature-rich Minecraft: Bedrock Edition server written in Java. Supports custom items, blocks, entities, full vanilla commands, advanced mob AI, and world generation. Not affiliated with Mojang AB.
asciidoctor / asciidoctorj
:coffee: Java bindings for Asciidoctor. Asciidoctor on the JVM!
OpenHFT / Chronicle-Core
Low level access to native memory, JVM and OS.
SAP / SapMachine
An OpenJDK release maintained and supported by SAP
slackapi / java-slack-sdk
Slack Developer Kit (including Bolt for Java) for any JVM language
irockel / tda
TDA - Thread Dump Analyzer (for Java). Analyze your Thread Dumps with a GUI or use it as MCP Server.
Incendo / cloud
Command framework & dispatcher for the JVM
shining-stars-l / javaup
🚀 超级八股文 🚀 - 告别死记硬背的 Java 全栈技术知识库！100万+字的讲解，原理剖析 + 丰富代码示例 + 清晰流程图解，让你真正理解每一个技术点！
quick-perf / quickperf
QuickPerf is a testing library for Java to quickly evaluate and improve some performance-related properties
optimatika / ojAlgo
Pure Java LP, QP and MIP solvers plus fast linear algebra. Zero dependencies, MIT licensed. Mathematical optimization and linear algebra for the JVM.
cucumber / cucumber-jvm-starter-maven-java
This is the simplest possible setup for Cucumber-JVM using Java with Maven.
KofLang / Kof4j
Uma linguagem. Um compilador. Vários mundos. se pronuncia coffe Menos código. Mais intenção. JVM, nativo, script e web. Tudo partindo da mesma linguagem.
NHCM-dev / JVMRTDP
A Java debugger & library which allows user and programmer to control remote JavaVMs