Top Welcoming Open-Source Java Repositories

Kieker is an observability framework, that consists of an monitoring and tracing agent, and compatible analysis tools

A game controller mapping tool crafted specifically for flight simulators

Virtual Cell Framework

Java SDK for Milvus.

Free & open-source reimplementation of Imperium Galactica. Download the Installer below the file list!

Simple and productive Web Development Tools in the Eclipse IDE

🔥 人人可用的开源 BI 工具，数据可视化神器。An open-source BI tool alternative to Tableau.

🦎 A lightweight, multi-protocol gateway for event-driven applications and AI agents. Expose and govern Kafka, MQTT, APIs, and MCP through one high-performance engine with shared routing, security, schema, and observability.

A code generator for MyBatis.

Parallel Collectors is a toolkit easing parallel collection processing in Java using Stream API.

Eclipse hawkBit™

Google Ads API Client Library for Java

A Fabric mod that brings (Neo)Forge mods into the Fabric ecosystem.

Quality Police for Java projects: aggregator of Checkstyle and PMD

A library to help you decode JWTs for Android

APM, Application Performance Monitoring System

SysON: web-based graphical modelers for SysMLv2. Please visit https://mbse-syson.org and contact Obeo https://www.obeosoft.com/en/contact for more details!

Open-source semantic layer: one cube for Excel (MDX/XMLA), dashboards, and AI agents (MCP). Mondrian + Apache Calcite.

Android application for Quad9 recursive DNS cybersecurity and privacy services

High-Performance Java-Native-Persistence. Store and load any Java Object Graph or Subgraphs partially, Relieved of Heavy-weight JPA. Microsecond Response Time. Ultra-High Throughput. Minimum of Latencies. Create Ultra-Fast In-Memory Database Applications & Microservices.

OsmAnd tools to generate new maps & to test OsmAnd files on PC

Modifications to the Minecraft base files to assist in compatibility between mods. New Discord: https://discord.minecraftforge.net/

TripleA is a turn based strategy game and board game engine, similar to Axis & Allies or Risk.

MekHQ is a campaign management tool that provides an immersive experience in managing a BattleTech mercenary unit. It integrates with MegaMek for battles and MegaMekLab for unit customization, covering personnel, finances, and logistics.

Multi-Agent Transport Simulation

Log viewer focused on developers work

Reitti is a comprehensive personal location tracking and analysis application that helps you understand your movement patterns and significant places. The name "Reitti" comes from Finnish, meaning "route" or "path".

The missing developer UI for Spring Boot and Quarkus!

KoLmafia is a cross-platform desktop tool which interfaces with the online adventure game Kingdom of Loathing 🗡️🍸

Akto is the fastest growing AI Security platform for your teams to secure AI agents, MCPs, LLMs, Agent skills, Gen AI apps in your organization.

A Java library for the Dropbox Core API.

Hyperledger Fabric Contract and Chaincode implementation for Java

A free and open source medication tracking app for Android 10+

Codehaus Cargo source code

Microscope control and image acquisition integrated with ImageJ

T.J. Watson Libraries for Analysis, with front ends for Java, Android, and JavaScript, and many common static program analyses.

Open-source framework for native apps from one Java codebase, with a custom-rendered UI you control across iOS, Android, desktop, web, and watches.

Easy User Management Framework/Starter App for Spring. Providing registration, login, logout, and more built on top of Spring Security.

Enterprise-grade, commercial-friendly agentic workflow platform for building next-generation SuperAgents.

GUI tool to edit GTA San Andreas savegames.

Provide support to increase developer productivity in Java when using Elasticsearch. Uses familiar Spring concepts such as a template classes for core API usage and lightweight repository style data access.

Mojarra, a Jakarta Faces implementation

A free and open-source database management tool, suitable for team use. It offers capabilities such as access control, data anonymization, SQL auditing, CI/CD, and supports cross-regional deployment.

Apache OFBiz is an open source product for the automation of enterprise processes. It includes framework components and business applications for ERP, CRM, E-Business/E-Commerce, Supply Chain Management and Manufacturing Resource Planning. OFBiz provides a foundation and starting point for reliable, secure and scalable enterprise solutions.

Open source IaC Automation and Collaboration Software.

A Java wrapper around the JSON API provided by TheMovieDB.org

Gameboy emulator in Java and Kotlin.

Wynntils (Artemis) is a rewrite of Wynntils in 1.21.11 using Architectury, to support Fabric and Forge.

EOLANG, an Experimental Pure Object-Oriented Programming Language Based on 𝜑-Calculus