Top 22 Open Source Java Projects to Enhance Your Development Skills

Did you know? Some of the most groundbreaking innovations in big data are powered by Java! From Apache Kafka revolutionizing event streaming to Apache Iceberg transforming data lakes and Trino enabling lightning-fast distributed SQL queries, these tools are making a massive impact on the industry! 

Open-source projects on GitHub provide an excellent opportunity to enhance your Java development skills while contributing to real-world applications. By working on these projects, you can tackle challenges across various domains such as web development, security, databases, and more. 

With over 17 million Indian developers contributing to open-source on GitHub, the learning potential is vast. Contributing to these projects not only helps you hone your skills but also gives you experience in industry best practices while connecting with a global community of developers.

This blog highlights 22 top open-source Java projects on GitHub, covering diverse areas like cloud computing, testing frameworks, and IoT, offering valuable skills and learning opportunities to advance your Java expertise.

Boost your software development career by enrolling in upGrad’s Online Software Development Courses and equip yourself with the knowledge to work on leading open-source projects in real scenarios. Join today!

What Are Open Source Java Projects? 

Open-source Java projects are software engineering projects whose code is publicly available for anyone to view, use, and contribute to. They are created and maintained by developers worldwide, and anyone, from beginners to experts, can jump in and help improve them. Popular platforms like GitHub and GitLab host thousands of open-source Java projects, covering everything from simple tools to complex applications.

Working on these projects lets you gain practical coding experience, from backend development to deploying on the cloud. You'll also learn to collaborate, use Git for version control, and follow professional coding standards. 

Java remains one of the most in-demand programming languages in the tech industry, and these top courses offer the perfect opportunity to deepen your expertise and advance your career in software development.

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• Professional Certificate Program in Cloud Computing & DevOps
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Now, let’s dive into some of the top open-source Java projects you can explore on GitHub. 

Top 22 Open Source Java Projects on GitHub

GitHub is home to some of the most powerful and innovative open-source Java projects that span various domains, from mobile web development and databases to apps and testing frameworks. 

In this section, you will explore 22 notable open-source Java projects to boost your development skills. Each project offers unique features, technologies, and challenges. 

This table will give you a snapshot of what each project is about before diving deeper into the details.

Also Read: Java Tutorial: Learn Java Programming From Scratch For Beginners

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Now you have a complete list of 22 open source java projects, each with its own set of features, challenges, and learning opportunities.

Elasticsearch

Elasticsearch is a distributed search and analytics engine built for speed, scalability, and real-time search capabilities. It’s widely used for log or event data analysis, full-text search, and business intelligence applications.

Tools and Technologies: Java, Elasticsearch, Apache Lucene, JSON, RESTful APIs.

Unique Features:

• Real-time search and analytics across massive datasets.
• Distributed nature enables handling large volumes of data.

Skills Gained:

• Working with RESTful APIs.
• Data indexing and search algorithms.

Challenges:

• Optimizing search queries for speed and efficiency.
• Ensuring data consistency in a distributed environment.

Applications in Real World:

Let’s say you're working for a cybersecurity team, and you need to detect threats in real-time. Using Elasticsearch, you can index logs from various sources and quickly search through massive datasets to identify unusual patterns. This allows your team to spot and respond to threats instantly.
Alternatively, imagine you’re building a business intelligence dashboard for a retail company. With Elasticsearch, you can index transaction data and provide real-time search capabilities, enabling managers to analyze sales trends and customer behavior on the fly, leading to quicker, data-driven decisions.

Elasticsearch is one of the essential open source java projects to work on if you're interested in big data, distributed systems, or search technologies. 

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Also Read: How to Code, Compile, and Run Java Projects in 2025

Strongbox

Strongbox is an open-source repository management system that focuses on security, encryption, and key management. It helps teams manage sensitive data and cryptographic keys securely.

Tools and Technologies: Java, Apache Maven, Spring Security, JAX-RS (Java API for RESTful Web Services)

Unique Features:

• Provides encrypted storage for sensitive data.
• Supports integration with popular build tools like Maven.

Skills Gained:

• Implementing encryption and security protocols in Java.
• Working with RESTful APIs for secure data exchange.

Challenges:

• Ensuring data integrity and security across the system.
• Managing key rotations and ensuring encryption standards are followed.

Applications in the Real World:

In an enterprise-level software development setting, Strongbox can be used to store and manage API keys and sensitive configurations securely. By encrypting data and ensuring compliance with industry standards, you’ll help prevent unauthorized access to crucial data.

Strongbox is one of the most valuable open source java projects to work on if you're interested in security, encryption, and secure system design.

Also Read: Learn 50 Java Projects With Source Code (2025 Edition)

Glasscutter

Glasscutter is an open-source framework designed for cross-platform UI testing. It enables developers to test Java applications across multiple platforms, ensuring a consistent user experience and functionality regardless of the operating system. 

Tools and Technologies: Java, JUnit, Selenium, TestNG.

Unique Features:

• Cross-platform testing capabilities (Windows, macOS, Linux).
• Automates interaction with UI elements, such as buttons and text fields.

Skills Gained:

• Writing automated UI tests for Java applications.
• Debugging and resolving UI-related issues early in development.

Challenges:

• Ensuring UI tests are stable and work across different environments.
• Managing complex user interactions in the test scripts.

Applications in the Real World:

If you are developing a Java desktop application, Glasscutter can be used to ensure the app’s UI behaves correctly across Windows, macOS, and Linux, saving you time and manual testing efforts.

Glasscutter is one of the perfect open source java projects for developers interested in improving the reliability of their applications by automating UI tests and ensuring a seamless user experience across platforms.

JabRef

JabRef is an open-source reference management software that allows researchers and developers to organize and manage their bibliographic data. It supports a variety of citation styles and integrates seamlessly with LaTeX, making it a popular choice among researchers in fields like computer science and engineering.

Tools and Technologies: Java, JavaFX, BibTeX, LaTeX, SQLite

Unique Features:

• Supports BibTeX and BibLaTeX for LaTeX-based referencing.
• Powerful search and filtering options for large reference collections.

Skills Gained:

• Working with citation management and academic tools.
• Integrating third-party APIs for external data sources.

Challenges:

• Handling the complexity of different citation styles and formats.
• Syncing and managing references across multiple devices.

Applications in the Real World:

If you’re an academic researcher working on a paper, JabRef will allow you to easily manage and format your references, automatically generating LaTeX-compatible citation lists for your research.

JabRef is a great project to contribute to if you're interested in working with academic tools, managing bibliographic data, and integrating external databases into Java applications.

Wikimedia Commons App

The Wikimedia Commons App is an open-source mobile application designed to interact with Wikimedia Commons, the vast repository of free-use media files. The app allows users to browse, upload, and contribute media to the platform, facilitating easy access to millions of images, audio, and video files for educational and creative use.

Tools and Technologies: Java, Kotlin (for Android development), Wikimedia APIs, Retrofit (for network calls), SQLite (for local data storage).

Unique Features:

• Allows users to upload and download media files from Wikimedia Commons.
• Features seamless integration with the Wikimedia API for accessing media data.

Skills Gained:

• Building mobile apps using Java and Kotlin for Android.
• Working with RESTful APIs for seamless data exchange.

Challenges:

• Ensuring a smooth user experience when interacting with large media files.
• Managing user authentication and access control for uploads.

Applications in Real World:

The Wikimedia Commons App can be used by educators to upload and share educational images or videos, helping students access valuable resources directly from their mobile devices.

The Wikimedia Commons App is an excellent project to get involved with if you're interested in mobile development, media management, and contributing to the world of open-source media.

XWiki

XWiki is one of the open source java projects that allows organizations to create, manage, and share knowledge in a collaborative environment. It offers advanced features like structured data, customizable workflows, and a powerful API, making it ideal for knowledge management in both small and large enterprises. 

Tools and Technologies: Java, Hibernate, Spring Framework, Velocity (templating engine), Apache Lucene (search capabilities).

Unique Features:

• Highly customizable, with a rich set of plugins for additional functionality.
• Supports structured data, allowing for more complex and organized content.

Skills Gained:

• Developing scalable web applications with Java and Spring.
• Implementing and customizing templating engines like Velocity.

Challenges:

• Managing large volumes of data and ensuring fast, efficient search capabilities.
• Customizing the platform to meet specific organizational needs.

Applications in Real World:

XWiki can be used in a corporate environment to manage internal documentation, providing employees with easy access to knowledge articles, project updates, and internal resources.

Also Read: Best Java Courses (Java Developer Recommended)

Zerocode

Zerocode is an open-source framework designed to simplify automated testing for Java-based applications. It focuses on creating clear, concise, and human-readable test cases that can be used for integration and end-to-end testing, without the need for complex programming. 

Tools and Technologies: Java, JSON, YAML, JUnit, RESTful APIs.

Unique Features:

• Simplifies integration testing for RESTful services and microservices.
• Supports parallel test execution for faster feedback.

Skills Gained:

• Writing and executing automated integration tests.
• Working with RESTful APIs and testing web services.

Challenges:

• Handling complex test scenarios with minimal configuration.
• Ensuring that tests are maintainable and scalable over time.

Applications in Real World:

If you're working in a microservices environment, Zerocode can automate the testing of all API endpoints in a simple, efficient manner, helping to ensure robust and error-free interactions between services.

Zerocode is an ideal project for developers and testers who want to streamline the testing process, improve test automation, and enhance their skills in integration testing.

SirixDB

SirixDB is an open-source, versioned database designed to handle large-scale, transactional data. Unlike traditional databases, SirixDB stores all data versions, allowing you to track changes over time and retrieve any historical state of your data. 

Tools and Technologies: Java, SirixDB (core database engine), Tree-based indexing, Transactional data models.

Unique Features:

• Stores all versions of data, allowing you to retrieve any historical state.
• Highly optimized for handling large, time-series datasets.

Skills Gained:

• Understanding of versioned databases and time-travel querying.
• Implementing efficient indexing mechanisms for large-scale data.

Challenges:

• Managing the storage and retrieval of large datasets with multiple versions.
• Optimizing performance when querying over extensive time periods.

Applications in Real World:

If you're developing an IoT solution where sensor data needs to be tracked over time, SirixDB allows you to store each version of the data and query past states, making it ideal for real-time data analysis and monitoring.

SirixDB is an excellent choice for those interested in versioned databases and handling data that changes over time.

Also Read: Cloud Computing Projects in Java

Robolectric

Robolectric is an open-source testing framework that allows developers to write unit tests for Android applications without needing an emulator or a physical device. It simulates Android's framework on the JVM, making it faster and more efficient to run tests on your local machine.

Tools and Technologies: Java, Robolectric, JUnit, Android SDK.

Unique Features:

• Provides a fast, in-memory simulation of Android components like Views and Activities.
• Supports testing across different Android versions and devices using a unified testing environment.

Skills Gained:

• Writing fast, reliable unit tests for Android applications.
• Understanding Android framework internals and simulating them for testing.

Challenges:

• Ensuring that tests accurately reflect behavior across different devices and Android versions.
• Handling the limitations of in-memory simulation, which may not fully replicate device behavior in some cases.

Applications in Real World:

If you’re working on an Android app, Robolectric allows you to test components like UI interactions and lifecycle methods quickly without relying on a physical device, speeding up the development process and ensuring higher quality.

Robolectric is one of the open source java projects for developers focused on improving testing efficiency in Android development. It allows you to create fast and reliable tests, ultimately enhancing your app's quality while reducing testing time.

dotCMS

dotCMS is an open-source content management system (CMS) built on Java that allows developers to manage digital content across websites, apps, and other platforms. It is designed for scalability and flexibility, making it an excellent choice for both small businesses and large enterprises.

Tools and Technologies: Java, Spring Framework, Elasticsearch, Freemarker (templating engine), MySQL/PostgreSQL (database).

Unique Features:

• Robust content management system with multi-channel support (web, mobile, IoT).
• Advanced content versioning and approval workflows.

Skills Gained:

• Developing scalable CMS platforms using Java and Spring.
• Working with templating engines like Freemarker for dynamic content rendering.

Challenges:

• Ensuring seamless integration with third-party systems and APIs.
• Maintaining flexibility while adhering to enterprise-level performance and security standards.

Applications in Real World:

If you're managing a large-scale website for an enterprise, dotCMS can be used to deliver content to different platforms, allowing for personalized experiences for users while also streamlining content creation and approval processes.

dotCMS is a great project to contribute to if you’re looking to enhance your skills in building scalable, enterprise-level CMS platforms and integrating content management with other digital systems.

Also Read: How to Make a Successful Career in Java in 2025

Apache Tika

Apache Tika is an open-source content detection and extraction framework that allows developers to parse and extract text, metadata, and language from a wide variety of file formats. Its ability to detect and extract information automatically makes it invaluable for data management and analysis tasks.

Tools and Technologies: Java, Apache Tika (core library), Apache POI (for Microsoft Office formats), PDFBox (for PDF files), Tesseract (for OCR support).

Unique Features:

• Detects the MIME type of documents to determine the content type.
• Includes built-in Optical Character Recognition (OCR) support for image-based content extraction.

Skills Gained:

• Working with file formats and document parsing in Java.
• Implementing content extraction and indexing solutions.

Challenges:

• Handling large, diverse datasets with multiple file formats.
• Managing performance and memory consumption when processing large files.

Applications in Real World:

If you're building a legal search engine, Apache Tika can be used to extract text and metadata from PDFs, Word documents, and images, enabling efficient document indexing and search functionality across multiple formats.

Apache Tika is an essential tool if you're interested in working with content extraction, data indexing, or building applications that need to handle and process a wide range of file formats.

GraalVM

GraalVM is an open-source, high-performance virtual machine that supports multiple languages, including Java, JavaScript, Ruby, Python, and others. It allows developers to run applications written in different languages within the same JVM, offering significant performance improvements and enhanced interoperability. 

Tools and Technologies: Java, GraalVM (VM and JDK), JavaScript, Python, Native-image tool

Unique Features:

• Native-image compilation for faster startup and lower memory consumption.
• Optimized JIT (Just-in-Time) compilation for performance improvements in JVM languages.

Skills Gained:

• Developing multi-language applications and leveraging GraalVM’s polyglot features.
• Enhancing application performance with advanced JVM and JIT optimizations.

Challenges:

• Managing and debugging polyglot applications involving multiple programming languages.
• Ensuring compatibility with existing Java libraries and frameworks when using GraalVM.

Applications in Real World:

If you’re working on a microservices architecture where different services are written in different languages (e.g., Java and Python), GraalVM allows you to run them within the same JVM, streamlining development and enhancing performance.

GraalVM is one of the open source java projects that you must try if you're interested in performance optimization, multi-language interoperability, and the future of JVM-based development.

OpenSearch

OpenSearch is an open-source search and analytics engine that was originally derived from Elasticsearch. It is particularly useful for applications that require real-time search capabilities, like monitoring systems, e-commerce sites, and data-heavy platforms. 

Tools and Technologies: Java, OpenSearch (core engine), Apache Lucene, RESTful APIs, Kibana (for data visualization).

Unique Features:

• Full-text search and analytics with support for complex queries.
• Open-source with active community contributions and rich plugin support for additional functionalities.

Skills Gained:

• Implementing and managing search and analytics platforms.
• Building real-time, data-driven applications with complex query capabilities.

Challenges:

• Ensuring the performance and scalability of search queries as data grows.
• Managing distributed systems and data consistency across nodes.

Applications in Real World:

In an e-commerce environment, OpenSearch can be used to index product data, enabling fast searches for customers. It can also be used for real-time analytics, tracking sales trends and user behavior for better decision-making.

OpenSearch is an essential tool for those looking to dive into distributed search and analytics systems while gaining hands-on experience with one of the most powerful search engines in the open-source community.

Also Read: Top Spring Boot Features for Java Developers in 2025

ThingsBoard

ThingsBoard is an open-source Internet of Things (IoT) platform that enables users to collect, process, and visualize data from various IoT devices. With its flexible and extensible architecture, ThingsBoard is well-suited for building IoT solutions in industries like manufacturing, smart cities, agriculture, and energy management.

Tools and Technologies: Java, Spring Framework, MQTT, Apache Cassandra, PostgreSQL

Unique Features:

• Real-time device management and monitoring capabilities.
• Built-in support for data visualization through dashboards and widgets.

Skills Gained:

• Developing IoT applications and systems using Java and Spring.
• Implementing real-time data processing and analytics.

Challenges:

• Managing large volumes of data from multiple IoT devices in real-time.
• Ensuring secure device communication and data integrity.

Applications in Real World:

If you're working on a smart city project, ThingsBoard can be used to collect data from sensors such as traffic lights or pollution monitors, visualize that data in real-time, and enable city officials to monitor and make decisions quickly.

ThingsBoard is an ideal project to work on if you're interested in building scalable IoT solutions. It allows you to tackle real-world challenges related to real-time data processing, device management, and integration with various sensors and hardware platforms.

Java Design Patterns

Java Design Patterns are proven, reusable solutions to common software design problems. These patterns provide standard approaches to designing and structuring software in a way that promotes flexibility, scalability, and maintainability.

Tools and Technologies: Java, Object-Oriented Programming (OOP) principles, UML (Unified Modeling Language) for visualizing patterns.

Unique Features:

• A collection of best practices that help developers avoid common pitfalls in software design.
• Improves code readability, maintainability, and extensibility by using well-known, structured approaches.

Skills Gained:

• Understanding and implementing core design principles like encapsulation, inheritance, and polymorphism.
• Designing scalable and maintainable code architectures using proven patterns.

Challenges:

• Selecting the appropriate design pattern for a given problem.
• Ensuring that patterns are applied consistently across the application.

Applications in Real World:

If you're building a large-scale e-commerce platform, Java Design Patterns like the Singleton pattern for managing database connections or the Factory pattern for creating product instances will ensure your system is modular, maintainable, and scalable.

Java Design Patterns provide invaluable tools for developers looking to create high-quality, maintainable software. By learning and applying these patterns, you can write more efficient, readable, and scalable Java code, ultimately improving your software development skills.

Also Read: Software Design Patterns: A Complete Guide for 2025

Arduino

Arduino is an open-source electronics platform based on simple hardware and software. It is widely used for building interactive projects involving sensors, motors, lights, and other electronics. Its ease of use and active community make it a go-to platform for hobbyists, students, and professionals working with hardware and embedded systems.

Tools and Technologies: Arduino IDE (Integrated Development Environment), C/C++ (programming language), Arduino boards (e.g., Uno, Nano, Mega), Sensors and actuators (e.g., temperature sensors, motors, LEDs), Communication protocols (e.g., I2C, SPI, UART).

Unique Features:

• Open-source hardware and software, with a wide variety of pre-built libraries and components.
• Supports both beginner-level and advanced projects, from simple LED blinkers to complex robotic systems.
• A large community with extensive tutorials, projects, and support.

Skills Gained:

• Working with embedded systems and hardware programming.
• Writing code to interface with sensors and actuators.
• Understanding communication protocols and integrating them into projects.

Challenges:

• Managing hardware limitations such as memory, processing power, and power consumption in larger projects.
• Debugging hardware issues, such as faulty sensors or wiring, in complex systems.

Applications in Real World:

If you're working on an automated garden system, you can use Arduino to control sensors for soil moisture and automate watering, making gardening smarter and more efficient through embedded technology.

Arduino is an excellent project if you're looking to dive into the world of hardware development, create interactive systems, or bring your ideas to life with physical computing. It blends programming with electronics, providing a hands-on learning experience.

Also Read: Top 7 Arduino Projects Ideas & Topics For Beginners

Blynk

Blynk is an open-source platform used to build mobile applications for the Internet of Things (IoT) projects. It allows developers to easily control and monitor hardware devices from a smartphone or tablet. With its drag-and-drop interface, users can design custom mobile interfaces to interact with IoT devices, making it ideal for prototyping and quick deployment of IoT solutions.

Tools and Technologies: Arduino, ESP32, Raspberry Pi, and other IoT platforms, Blynk app (iOS and Android), Blynk Cloud (for device communication and data storage), MQTT, HTTP, and WebSockets (for communication).

Unique Features:

• Drag-and-drop mobile app builder for creating custom user interfaces.
• Real-time device control and monitoring from any mobile device.

Skills Gained:

• Designing mobile applications for controlling IoT devices.
• Working with cloud platforms and APIs to handle device data and communication.

Challenges:

• Optimizing mobile app performance for large-scale IoT deployments.
• Ensuring secure data transmission and user authentication for IoT applications.

Applications in Real World:

Imagine you’re working on a smart home project where you can control the lighting, security cameras, and HVAC system directly from a smartphone using Blynk, making IoT technology more accessible and customizable.

Blynk is perfect for those interested in developing IoT solutions quickly with minimal coding effort while still gaining experience in mobile app development, hardware integration, and cloud-based IoT management.

Mindustry

Mindustry is an open-source, resource management strategy game that blends real-time strategy (RTS) gameplay with tower defense elements. Players build and manage supply chains, produce resources, and defend their structures from waves of enemies. 

Tools and Technologies: Java, LibGDX (game development framework), OpenGL (for rendering), JSON (for game data and configuration).

Unique Features:

• Supports complex resource management and logistics systems.
• Modding capabilities, allowing the community to create custom maps and content.

Skills Gained:

• Game development and optimization techniques using Java and LibGDX.
• Designing resource management systems and automation strategies.

Challenges:

• Balancing game mechanics to ensure engaging and challenging gameplay.
• Managing the performance of complex, resource-heavy simulations during multiplayer sessions.

Applications in Real World:

If you’re interested in game development, Mindustry provides an opportunity to work on optimizing resource management systems and multiplayer features, offering valuable insights into both game design and performance optimization.

Mindustry is a great project for Java developers interested in game development, providing a chance to work with complex systems like resource management, automation, and multiplayer environments.

Also Read: Top 19 Exciting Spring Boot Projects & Topics for Beginners

Sndcpy

Sndcpy is an open-source application that allows you to stream audio and mirror the screen of an Android device to a computer via USB or Wi-Fi. It’s widely used by developers, testers, and users who need to mirror their Android device’s display with minimal delay, making it ideal for testing apps, presentations, or even playing mobile games on a larger screen.

Tools and Technologies: C/C++ (Core application), Android Debug Bridge (ADB), Audio and Video Encoding Libraries (e.g., FFmpeg), USB and TCP/IP protocols for communication.

Unique Features:

• High-performance, low-latency streaming of both screen and audio.
• Works without requiring root access on Android devices.

Skills Gained:

• Understanding of Android’s ADB and screen mirroring capabilities.
• Integrating low-latency communication protocols to ensure seamless device mirroring.

Challenges:

• Managing synchronization between audio and video streams across different devices.
• Handling varying device performance and connectivity to maintain smooth streaming.

Applications in Real World:

If you’re an Android developer, Sndcpy can be used to test apps in real time by mirroring your Android screen on a larger display, allowing you to interact with your app directly and test the user interface with minimal delay.

Sndcpy is a fantastic project if you're interested in building high-performance, real-time communication tools, or if you want to explore the complexities of multimedia streaming and device mirroring.

Hyperledger Fabric

Hyperledger Fabric is an open-source, permissioned blockchain framework designed for enterprise use. It provides a modular architecture that allows organizations to set up their own blockchain networks for secure, transparent, and efficient transaction processing. 

Tools and Technologies: Go (Programming Language for Smart Contracts), Hyperledger Fabric SDK, Docker (for containerization), Kubernetes (for orchestration), CouchDB (for storing data).

Unique Features:

• Permissioned blockchain: Only authorized participants can join the network, ensuring data privacy.
• Support for smart contracts (chaincode) that allow users to enforce business logic.

Skills Gained:

• Developing and deploying blockchain applications with smart contracts.
• Building and managing permissioned blockchain networks.

Challenges:

• Configuring and managing complex blockchain networks and ensuring secure participant management.
• Integrating with legacy systems and ensuring data consistency across different platforms.

Applications in Real World:

Imagine you're working on a supply chain solution where businesses need to track the journey of goods from the manufacturer to the consumer. Using Hyperledger Fabric, you can build a blockchain network that ensures transparency and security for all participants in the supply chain.

Hyperledger Fabric is one of the essential  Java open source projects for anyone looking to dive into enterprise-level blockchain solutions, offering the tools and flexibility to address complex use cases across various industries.

JHipster

JHipster is an open-source development platform that helps developers generate, develop, and deploy modern web applications and microservices. It combines the power of Java, Spring Boot, and Angular/React/Vue for full-stack development, allowing you to create robust and scalable applications quickly. 

Tools and Technologies: Java, Spring Boot, Angular/React/Vue (Frontend frameworks), Docker, Kubernetes, PostgreSQL/MySQL (Databases).

Unique Features:

• Generates both frontend and backend code for full-stack applications.
• Integration with cloud platforms (e.g., AWS, Azure) and containerization tools (Docker/Kubernetes).

Skills Gained:

• Developing microservices-based applications for scalability and modularity.
• Working with cloud-native architectures and DevOps tools for CI/CD.

Challenges:

• Learning how to manage and deploy microservices in a production environment.
• Configuring integration between backend services, frontend applications, and third-party APIs.

Applications in Real World:

If you’re working on building a web application for an online retailer, JHipster can help you generate a full-stack solution with microservices architecture, enabling fast development and seamless scalability.

JHipster is one of the best  Java open source projects for developers who want to quickly set up modern web applications or microservices, combining best practices in development, deployment, and scalability.

Spring Boot

Spring Boot is an open-source Java-based framework used to build stand-alone, production-grade applications quickly and easily. It simplifies the setup and development of new Spring applications by providing pre-configured templates and reducing the need for boilerplate code. 

Tools and Technologies: Java, Spring Framework, Spring Boot Starter Projects, Maven/Gradle (Build Tools), Spring Security, Spring Data, Spring Cloud.

Unique Features:

• Automatically configures your application based on the dependencies you include, reducing the need for manual configuration.
• Built-in features for creating and managing microservices-based architectures.

Also Read: Top Spring Boot Features for Java Developers

Skills Gained:

• Building RESTful APIs and web applications with minimal setup.
• Integrating security, data access, and messaging frameworks into Spring Boot applications.

Challenges:

• Learning how to manage and configure complex dependencies within a Spring Boot application.
• Balancing the use of auto-configuration to avoid performance issues or unneeded components.

Applications in Real World:

Imagine you're tasked with creating an API for a logistics company. With Spring Boot, you can quickly develop and deploy a RESTful API that communicates with the company’s database, handles user authentication, and integrates with external shipping systems.

Spring Boot is among the fantastic Java open source projects for developers looking to dive deeper into backend development with Java. It simplifies complex setups and allows you to focus on building functional and scalable applications.

Also Read: Top 8 Java Open Source Projects You Should Get Your Hands-on [2024] | upGrad blog

Now that we’ve explored some exciting Java open-source projects, let’s take a closer look at the benefits of contributing to these projects and how they can significantly impact your growth as a developer.

Benefits of Contributing to Java Open Source Projects

Contributing to Java open source projects is a powerful way to enhance your skills and advance your career. By working on real-world problems, collaborating with experienced developers, and gaining exposure to professional codebases, you’ll build a strong portfolio that catches the eye of employers. 

In the following points, you’ll discover how these contributions can directly benefit your growth as a developer.

1. Sharpen Your Coding Skills with Real-World Problems
    Concern: “I feel like I’m stuck in a coding rut with personal projects. Will this really make a difference?”
    Reality: Open-source projects provide the perfect environment to push your limits. You’ll work with real-world problems and large-scale codebases, giving you a chance to practice best practices and improve your problem-solving skills.
    Example: Imagine you’re working on an issue with Elasticsearch – you’ll dive deep into distributed systems, learning how to handle scalability, performance optimization, and fault tolerance. You’ll learn things that most personal projects can’t teach you.
2. Collaborate and Learn from Skilled Developers
    Concern: “How can I learn from experienced developers if they’re too busy?”
    Reality: Open-source communities are built around collaboration. Experienced developers are eager to help and review your code. You’ll get valuable feedback on your coding style, structure, and even design decisions, which can be hard to get from solo work.
    Example: By contributing to a project like JabRef, which deals with real-world database interactions, you’ll work alongside seasoned developers, learning the finer points of clean code, database optimization, and handling edge cases.
3. Build a Network that Opens Doors
    Concern: “I’m a bit introverted—how do I network in an online, global community?”
    Reality: Contributing to open-source projects naturally opens doors to connecting with developers worldwide, even if you're shy about networking. Through GitHub discussions, project collaborations, or online open-source events, you’ll build relationships that can lead to job offers or partnerships.
    Example: Imagine working on an issue with a developer based in another country. Over time, you might collaborate on more projects, exchanging ideas and advice, which could even lead to a job referral or an international collaboration down the road.
4. Boost Your Resume with Real-World Projects
    Concern: “Will contributing to open source really help me land a job? Isn’t it just a side hobby?”
    Reality: Yes, it absolutely will. Contributing to popular open-source projects shows potential employers that you're proactive, have real-world coding experience, and are committed to learning and growing. It’s a concrete way to stand out in a crowded job market.
    Example: Contributing to well-known projects like Spring Boot or Apache Tika gives you something tangible to put on your resume. You can showcase specific features or fixes you've worked on, proving that you can work on large, professional-grade projects.
5. Gain Practical Experience with Industry-Standard Tools
    Concern: “I don’t want to fall behind in terms of the latest technologies. Will I be exposed to the right tools?”
    Reality: Open-source projects often use the latest tech and industry-standard tools. This exposure helps you stay current, and you’ll walk away with knowledge that’s directly applicable to your work or personal projects.
    Example: If you contribute to a project using Git for version control or CI/CD tools like Jenkins, you’ll not only become proficient with them but also learn best practices that are standard in the industry. This hands-on experience will be incredibly valuable whether you’re working at a startup or a large company.

Are you ready to level up your coding skills and make a real impact in the development world? Contributing to Java open-source projects is the perfect way to grow, connect, and stand out. And to help you get started, we’ve got free courses and resources tailored just for you, so you can dive in with confidence!  

Also Read: 14 Key Advantages of Java Programming for Developers

As you enhance your skills through contributing to open source, the next step is to harness your knowledge and turn it into a successful career. Let’s explore how upGrad can provide the guidance and resources to help you do just that.

How upGrad Can Help You Build a Career in Java Development?

Exploring these 22 open-source Java projects has given you valuable insights into diverse opportunities for skill growth. Whether in web development, IoT, security, or game development, these projects offer hands-on experience and practical problem-solving.

To accelerate your learning, upGrad’s expert-led courses provide structured paths and mentorship, helping you fill any knowledge gaps. With a focus on practical application and career advancement, upGrad is the perfect platform to elevate your skills and unlock new career opportunities in tech.

In addition to the programs mentioned above, here are some more free courses to further enhance your learning and skills:

• Core Java Basics
• Object Oriented Analysis and Design for Beginners
• Advanced JavaScript for All
• Object Oriented Principles in Java
• Data Structures & Algorithms

You can contact upGrad’s expert career counselors, who will guide you based on your goals. You can also visit a nearby upGrad offline center to explore course options, get hands-on experience, and speak directly with mentors! 

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References:

https://github.com/trending/java