Open Source Java Projects
Java is a general-purpose programming language and runtime platform used to build applications that run across operating systems and devices. Its strong type system, mature tooling, and broad ecosystem help teams develop server-side services, desktop software, mobile applications, and data-processing systems. Java is also used where long-term support, portability, and integration with established infrastructure are important.
Open source Java tools include frameworks, libraries, developer utilities, monitoring systems, and learning resources. When choosing one, consider its license, documentation, release history, maintenance activity, supported Java versions, security practices, and compatibility with your existing stack. Check whether its requirements fit your deployment environment and whether it can integrate with the services and build tools you already use. These resources are useful to beginners, application developers, platform teams, and organizations maintaining or modernizing Java systems.
18 repositories · updated October 15, 2026
rag-agent-platform: Self-Host RAG Agents and MCP Tools
A self-hosted Java and Next.js platform for combining document retrieval, LLM-powered agents, and MCP tools. It suits teams that want a configurable knowledge and agent workflow under their own infrastructure, with external services to operate.
ActiveHealth 32/100
awesome-java: Find Java Frameworks, Libraries, Tools, and Resources
A community-curated directory of Java frameworks, libraries, tools, and learning resources. Browse 839 projects across 81 categories to compare options for common development tasks.
ActiveHealth 51/100
opendataloader-pdf: Extract Structured Data and Add Accessibility Tags to PDFs
OpenDataLoader PDF turns digital, scanned, and tagged PDFs into structured formats for AI and RAG workflows, and can auto-tag untagged PDFs. It offers Java, Python, and Node.js SDKs, with local and hybrid processing modes.
ActiveHealth 68/100
CompreFace: Run Self-Hosted Face Recognition APIs
CompreFace is a Docker-based face analysis service with REST APIs for recognition, verification, detection, and related tasks. It suits teams that need to integrate face processing into applications while keeping deployment on their own infrastructure.
InactiveHealth 43/100
openaev: Plan and Run Cyber Adversary Simulations
OpenAEV helps security teams plan, schedule, and run adversary simulation campaigns and exercises. Use it to coordinate teams, monitor activity, and review security gaps in relation to current threats.
ActiveHealth 81/100
java-sdk: Build Model Context Protocol Clients and Servers in Java
The official Java SDK for building MCP clients and servers, with synchronous and asynchronous APIs and multiple transport options. It is actively maintained and suits Java teams integrating applications with MCP tools and services.
ActiveHealth 67/100
supertokens-core: Build Authentication Into Your Applications
SuperTokens Core is a self-hostable authentication service that handles core login, user, and session operations for backend SDKs. It suits teams that want managed auth features while keeping user data in their own database and deployment.
ActiveHealth 69/100
hertzbeat: Monitor Systems, Metrics, Logs, and Alerts
Apache HertzBeat is a self-hosted observability platform for collecting metrics and logs, managing alerts, and publishing service status pages. It suits teams seeking agentless monitoring with configurable collection and optional collector clusters.
ActiveHealth 67/100
quarkus: Build Cloud-Native Java Applications
Quarkus is a Java framework for building container-oriented applications that run on the JVM or as native executables. It combines imperative and reactive development and emphasizes fast startup and a build-time-focused workflow.
ActiveHealth 74/100
starrocks: Query Lakehouse and Analytics Data with SQL
StarRocks is a distributed SQL query engine for real-time and ad-hoc analytics across managed tables and data lakes. It suits teams that need low-latency analytical queries, concurrent updates, and scale-out deployment.
ActiveHealth 70/100
kafka-ui: Manage and Monitor Apache Kafka Clusters
A web UI for monitoring and managing Apache Kafka clusters from one place. It helps Kafka operators and developers inspect brokers, topics, consumer groups, and messages, and configure cluster workflows through a browser.
InactiveHealth 39/100
selenium: Automate Web Browsers Across Languages
Selenium is a browser automation framework built around the W3C WebDriver standard. It helps developers and testers automate browser interactions across major browsers using bindings for several programming languages.
ActiveHealth 75/100