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Top 23 Java Java Projects
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InfluxDB
InfluxDB – Built for High-Performance Time Series Workloads. InfluxDB 3 OSS is now GA. Transform, enrich, and act on time series data directly in the database. Automate critical tasks and eliminate the need to move data externally. Download now.
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Spring Boot
Spring Boot helps you to create Spring-powered, production-grade applications and services with absolute minimum fuss.
When I started developing LangGraph4j, I tried to replicate my Python development ecosystem in Java. So I've experimented with the Java Notebooks through the rapaio-jupyter-kernel project, which allowed me to replicate the development experience I had with Jupyter Notebooks in Python quite well. For rapid prototyping, I relied almost entirely on Spring Boot framework, which is a fairly fast and enjoyable programming experience.
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advanced-java
😮 Core Interview Questions & Answers For Experienced Java(Backend) Developers | 互联网 Java 工程师进阶知识完全扫盲：涵盖高并发、分布式、高可用、微服务、海量数据处理等领域知识
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Let's go further, now we talk about the error from Elasticsearch.
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Stream
Stream - Scalable APIs for Chat, Feeds, Moderation, & Video. Stream helps developers build engaging apps that scale to millions with performant and flexible Chat, Feeds, Moderation, and Video APIs and SDKs powered by a global edge network and enterprise-grade infrastructure.
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Project mention: Are you really wasting your time in Java without these 10 libraries? | dev.to | 2025-11-20
Apache Commons Lang and Google Guava play the same role in the ecosystem, even though the former predates the latter: fill in the gaps in the Java standard APIs. For example, one of the biggest current PITAs in modern Java is checked exceptions inside lambdas. Both libraries provide wrapping methods to handle this specific use case. In general, modern Java versions and Kotlin drastically diminish the need for these additional dependencies.
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RxJava
RxJava – Reactive Extensions for the JVM – a library for composing asynchronous and event-based programs using observable sequences for the Java VM.
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Project mention: CLI to manage your SQL database schemas and migrations | news.ycombinator.com | 2025-11-01
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JeecgBoot
🔥AI低代码平台，助力企业快速实现低代码开发和构建AI应用！ 成熟的AI应用平台：涵盖AI应用、AI模型、AI聊天助手、知识库、AI流程编排、MCP和插件，聊天式业务操作等，兼容多种大模型；提供强大代码生成器：实现前后端一键生成，无需手写代码! 引领AI开发模式：AI生成→在线配置→代码生成→手工合并，解决Java项目80%重复工作，提升效率节省成本，又不失灵活~
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Let's look at the example from Apache Dubbo:
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MPAndroidChart
A powerful 🚀 Android chart view / graph view library, supporting line- bar- pie- radar- bubble- and candlestick charts as well as scaling, panning and animations.
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Project mention: Top 7 Puppeteer Alternatives for Web Automation and Testing (2025) | dev.to | 2025-08-05
Selenium is one of the most popular and mature automated testing frameworks for web applications. Unlike Puppeteer, which is limited to Chromium, Selenium supports all major browsers—including Chrome, Firefox, Safari, and Edge—making it a reliable choice for Cross-platform browser testing.
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Project mention: React Native ile Endüstriyel Barkod Okuma: Ters Renk Data Matrix Kodları ve Zebra DataWedge Entegrasyonu | dev.to | 2025-12-19
ZXing (Zebra Crossing)
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conductor
Conductor is an event driven orchestration platform providing durable and highly resilient execution engine for your applications
Project mention: Conductor, an orchestration engine for microservices and event-driven workflows | news.ycombinator.com | 2025-10-05 -
Just to throw one on the pile https://github.com/yuliskov/smarttube for android based TV media box is great.
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Project mention: Top Open-Source Data Engineering Tools- Unravelling the Best in 2026 | dev.to | 2025-12-10
Kestra
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There are many open-source games. There are few large-scale high-polish open source games because it's difficult to build a business model around that. Unlike non-game software, games are ~exclusively consumer-facing, so you can't sell support or use them as a loss leader, and they're standalone applications that are difficult to monetize with online features or to use as the core of a closed-source commercial product.
That said, there are still lots of great projects out there (some of which have even had commercial success), for example:
- https://github.com/a327ex/SNKRX
- https://github.com/beyond-all-reason/Beyond-All-Reason
- https://github.com/endless-sky/endless-sky
- https://github.com/Anuken/Mindustry
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Project mention: AWS EKS Deployment: Real-Time Data Streaming Platform - 50K Events/Sec for $1,250/Month | dev.to | 2025-10-26
Apache Flink: flink.apache.org
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SaaSHub
SaaSHub - Software Alternatives and Reviews. SaaSHub helps you find the best software and product alternatives
NOTE:
The open source projects on this list are ordered by number of github stars.
The number of mentions indicates repo mentiontions in the last 12 Months or
since we started tracking (Dec 2020).
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A note from our sponsor - SaaSHub
www.saashub.com | 27 Dec 2025
Index
What are some of the best open-source Java projects in Java? This list will help you:
| # | Project | Stars |
|---|---|---|
| 1 | JavaGuide | 153,129 |
| 2 | Design Patterns | 93,544 |
| 3 | Spring Boot | 79,473 |
| 4 | advanced-java | 78,643 |
| 5 | Elasticsearch | 75,680 |
| 6 | interviews | 64,736 |
| 7 | Java | 64,595 |
| 8 | Guava | 51,364 |
| 9 | RxJava | 48,488 |
| 10 | dbeaver | 47,953 |
| 11 | jadx | 46,642 |
| 12 | JeecgBoot | 44,771 |
| 13 | Dubbo | 41,676 |
| 14 | MPAndroidChart | 38,189 |
| 15 | Arthas | 36,959 |
| 16 | spring-boot-demo | 33,954 |
| 17 | Selenium WebDriver | 33,817 |
| 18 | ZXing | 33,765 |
| 19 | conductor | 31,671 |
| 20 | SmartTube | 27,177 |
| 21 | kestra | 26,148 |
| 22 | Mindustry | 26,010 |
| 23 | Apache Flink | 25,636 |
Sponsored
InfluxDB – Built for High-Performance Time Series Workloads
InfluxDB 3 OSS is now GA. Transform, enrich, and act on time series data directly in the database. Automate critical tasks and eliminate the need to move data externally. Download now.
www.influxdata.com