Top 15 Open-Source GitHub Java Projects to Explore in 2025

GitHub hosts a wide range of Java projects, such as API backends, desktop tools, Spring-based web apps, and Android apps, that reflect today’s development demands. Working with these projects sharpens skills in microservices, RESTful design, CI/CD workflows, design patterns, and testing frameworks. Studying real code shows how software is built, tested, and maintained, preparing you for development work and career growth.

Exploring these projects helps improve problem-solving skills, exposes you to different coding styles, and keeps you updated with the latest Java practices, giving you a clear advantage in building skills and advancing your career.

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GitHub Java Projects: 15 Picks for Beginner to Advanced Developers

Exploring GitHub Java projects gives you practical experience in key areas like GUI development with Swing or JavaFX, networking using sockets, database management via JDBC, and API integration through REST. Whether you’re starting out or advancing your skills, these projects help you understand different coding styles and tools while preparing you for software development tasks.

GitHub Java Projects for Beginners

Starting simple is key to building a solid foundation. Here are five GitHub Java projects for beginners to get your feet wet:

1. Calculator App

Source: GitHub

A basic calculator is a perfect starting point to understand how Java handles user input and performs simple operations. This project focuses on creating an interactive interface where users can perform arithmetic calculations smoothly.

• Tools used: Java Swing, NetBeans/Eclipse IDE
• Key features: This project lets you build a simple desktop calculator capable of performing basic arithmetic operations like addition, subtraction, multiplication, and division. It includes a clear/reset button to start fresh, all wrapped in a clean, user-friendly interface.
• Applications: Beyond being a handy desktop utility, this project introduces you to graphical user interface (GUI) programming, an essential skill for interactive Java apps. The calculator logic mirrors systems like billing or POS applications, showing how the GUI and backend work together in practical software.
• Skills gained: You’ll get hands-on practice with event handling, designing windows and buttons using Swing, and reinforcing object-oriented principles by organizing your code efficiently.

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2. To-Do List Manager

Source: GitHub

This GitHub Java project for beginners builds a simple task management app that helps users organize their daily activities. It introduces you to UI design and managing data persistence, essential for any practical application.

• Tools used: JavaFX, IntelliJ IDEA
• Key features: You create a simple yet functional task manager where users can add new tasks, edit or delete existing ones, and prioritize them by importance. It also supports saving and loading tasks using file handling, ensuring your list persists between sessions.
• Applications: This app is a personal productivity tool that mimics actual task management applications.
• Skills gained: You'll learn how to design user interfaces with JavaFX, manage task lists using Java collections like ArrayList, and handle file input/output operations to save data locally through serialization, offering practical insight into data storage and management.

3. Simple Chat Application

Source: GitHub

Creating a chat app introduces you to networking basics. You’ll learn how to send and receive messages between users in real time, a foundational concept for many communication platforms.

• Tools used: Java Sockets, Multithreading
• Key features: Build a basic messaging platform allowing multiple clients to communicate in real time. The app supports broadcasting messages to all connected users and handles simple commands like private messaging or user lists.
• Applications: This project introduces the basics of network communication and forms the foundation of chat and collaboration tools.
• Skills gained: You’ll explore network programming with sockets, manage multiple users using multithreading, and grasp the client-server model behind apps like Slack or WhatsApp. This project can be expanded with features like logging and failover handling to deepen your understanding.

Also Read: Socket Programming in Java: A Brief Guide

4. Currency Converter

Source: GitHub

This app connects to live exchange rate services to provide up-to-date currency conversions. It’s a practical way to learn API integration and working with dynamic data in Java applications.

• Tools used: Java Swing, REST API integration, JSON parsing libraries like GSON
• Key features: This tool fetches up-to-date currency exchange rates from online APIs and lets users convert amounts between different currencies through a simple graphical interface.
• Applications: Useful for finance and travel, this project demonstrates how to integrate live data into desktop apps.
• Skills gained: You’ll gain experience calling RESTful APIs, parsing JSON responses using GSON, and displaying dynamic data through GUI components, applying networking and user interface design together. For example, you might work with APIs like exchangeratesapi.io to fetch live data.

5. Student Management System

Source: GitHub

A student management system simulates real database-driven applications by allowing data entry, updates, and queries. This project teaches how to interact with databases and handle data securely.

• Tools used: Java, JDBC, MySQL
• Key features: This system allows users to add new student records, update existing information, delete entries, and search for specific students. It connects to a MySQL database to store and retrieve data securely.
• Applications: Commonly used in schools and colleges, this system showcases practical database-driven application development.
• Skills gained: You’ll learn to integrate Java with relational databases using JDBC, perform CRUD operations, and write SQL queries. You’ll also get introduced to basic database design concepts like normalization and foreign keys, plus security practices such as preventing SQL injection to keep data safe.

GitHub Java Projects for Intermediate Level

If you’re new to professional Java but know the basics, these GitHub projects help build intermediate skills like backend web development with Spring, implementing security controls, and applying MVC design patterns to create organized, maintainable applications.

1. Inventory Management System

Source: GitHub

An inventory management system helps track stock levels, manage purchases and sales, and control user access, simulating real retail and warehouse operations. This project introduces key backend and frontend integration with a focus on efficient data handling.

• Tools used: JavaFX, MySQL, Hibernate ORM
• Key features: You’ll build a system that tracks inventory in real time, automatically updates stock after purchases and sales, secures access with user authentication, and generates detailed reports to keep everything transparent.
• Applications: This is what retailers, warehouses, and logistics teams use to keep their stock organized and operations smooth.
• Skills gained: Working with ORM frameworks like Hibernate, understanding database normalization, and implementing secure user access controls with role-based logic. You’ll also learn to generate reports using tools like JasperReports or dynamic SQL, adding depth to data management and security.

2. Online Voting System

Source: GitHub

In this project, you’ll create a secure online voting platform. Users can register to vote, cast their ballots anonymously, and instantly see live election results. You’ll incorporate safeguards to prevent users from voting multiple times and ensure data integrity. This system mirrors the complexities of real voting software, where security and privacy are paramount.

• Tools used: Java Servlet, JSP, MySQL
• Key features: User-friendly registration and login, secure vote casting with encryption, immediate results display, and measures to prevent double voting.
• Applications: This system applies to government elections, corporate shareholder voting, or any organizational decision-making process.
• Skills gained: You’ll learn to manage user sessions, securely authenticate users, and apply web security best practices. This includes techniques like encryption and hashing to protect vote privacy, plus structuring audit logs for transparency and accountability in voting systems.

Also Read: JSP vs Servlet: Difference Between JSP & Servlet [2025]

3. Expense Tracker

Source: GitHub

You’ll develop an intuitive expense tracker app that helps users record and categorize their daily spending. The app will generate detailed reports to visualize spending patterns and aid budgeting. This project combines frontend UI design with backend data handling to create a fully functional financial tool.

• Tools used: Spring Boot, Thymeleaf, MySQL
• Key features: Easy entry of expenses with category tagging, dynamic report generation showing spending trends, and a clean, responsive user interface.
• Applications: Ideal for personal finance management apps and budgeting tools.
• Skills gained: You’ll deepen your understanding of the Spring framework and MVC architecture, work with server-side rendering using Thymeleaf, and handle database operations efficiently. You’ll also learn to generate spending reports using techniques like data grouping, date-based filtering, and visual summaries to provide clear insights.

Also Read: Spring vs Spring Boot: Understanding the Difference Between Spring and Spring Boot in 2025

4. Library Management System

Source: GitHub

In this project, you’ll build a system that catalogs books, manages checkouts and returns, and differentiates user roles like librarians and members. You’ll implement transactional operations to ensure that book loans and returns are recorded accurately, along with access controls to manage user permissions.

• Tools used: Java, JDBC, MySQL
• Key features: Comprehensive book inventory, seamless issue and return processing, and role-based access for different user types.
• Applications: Perfect for libraries, schools, and digital archives that require organized book management.
• Skills gained: You’ll write SQL queries for data management, apply transaction control in scenarios like handling double book returns or race conditions to maintain consistency, and design secure user permission systems.

5. Online Quiz Portal

Source: GitHub

You’ll create an interactive quiz platform where users can design quizzes, take timed tests, and instantly receive their scores and feedback. The project requires integrating a ReactJS frontend with a Spring Boot backend, ensuring a smooth, dynamic experience.

• Tools used: Spring Boot, ReactJS, PostgreSQL
• Key features: Dynamic quiz creation tools, timer-controlled assessments to simulate exam conditions, automated scoring, and immediate result display.
• Applications: Suitable for e-learning platforms, online certifications, and corporate training modules.
• Skills gained: You’ll build full-stack applications by designing RESTful APIs and connecting frontend and backend components. For example, React sends quiz answers through the API, while Spring Boot processes, scores, and stores the results, showing how data flows smoothly between client and server.

Also Read: Full Stack vs Front End vs Back End Developers: Understanding the Differences

GitHub Java Projects for Advanced Level

For experienced Java developers, these projects challenge your design and architectural skills:

1. Banking System API

Source: GitHub

You’ll create a secure backend API that handles user accounts, processes transactions, and implements multi-factor authentication for added security. This project simulates real banking systems where protecting sensitive financial data is essential. You’ll design RESTful services that manage account operations and enforce strict security policies.

• Tools used: Spring Boot, Spring Security, JWT, PostgreSQL
• Key features: Multi-factor authentication, secure transaction processing, detailed audit logs, and role-based access control.
• Applications: Digital banking backends, fintech platforms, mobile banking APIs with compliance needs.
• Skills gained: Building secure REST APIs, implementing JWT-based authentication, and designing reliable microservices for financial data.

Also Read: Cyber Security in Banking: Challenges and Security Strategies for 2025

2. E-Commerce Platform

Source: GitHub

You’ll develop a fully functional online store featuring product catalogs, shopping cart functionality, payment processing, and optimized search. This project challenges you to manage data efficiently and deliver a seamless user experience, handling high traffic loads with caching and search technologies.

• Tools used: Spring Boot, Hibernate, Angular, Redis, Elasticsearch
• Key features: Dynamic product catalogs, persistent shopping carts, payment gateway integration, and Elasticsearch-powered search.
• Applications: Online stores, multi-vendor marketplaces, scalable enterprise retail platforms.
• Skills gained: You’ll excel at using Redis caching, integrating payment services, optimizing search, and managing complex ORM relationships.

3. Real-Time Chat Server

Source: GitHub

You’ll build a scalable chat server that supports instant messaging, group conversations, and persistent message storage. This project focuses on low-latency communication using WebSocket and efficient message handling to support many users simultaneously.

• Tools used: Netty, WebSocket, Redis
• Key features: WebSocket messaging, group chats, persistent chat history, and scalable user handling.
• Applications: Social media messaging, team collaboration tools, customer support chat systems.
• Skills gained: High-performance networking with Netty, real-time data streaming, scalable architecture design, and Redis-based message caching.

4. Healthcare Management System

Source: GitHub

You’ll design a system to manage patient records, appointment scheduling, and notifications, using event-driven architecture for responsiveness. This project demonstrates handling complex healthcare data with NoSQL storage and real-time communication between components.

• Tools used: Spring Boot, MongoDB, Kafka
• Key features: Secure patient records, real-time appointment booking, automated notifications, and event-driven system integration.
• Applications: Hospital management, telemedicine apps, healthcare provider systems.
• Skills gained: You’ll learn to model healthcare data with MongoDB, event-driven microservices with Kafka, building fault-tolerant distributed apps.

5. Machine Learning Pipeline in Java

Source: GitHub

You’ll implement a machine learning pipeline that handles data preprocessing, model training, evaluation, and deployment at scale. This project introduces you to big data frameworks and deep learning in Java, preparing you for AI-driven applications.

• Tools used: Deeplearning4j, Apache Spark, Hadoop
• Key features: Data ingestion and cleaning, distributed model training, evaluation metrics, and deployment automation.
• Applications: AI analytics, predictive maintenance, large-scale recommendation engines.
• Skills gained: Big data processing with Spark and Hadoop, deep learning with Deeplearning4j, automating ML workflows and deployments.

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Here are 15 standout open-source GitHub Java projects to jumpstart your coding journey. You’ll find source code links at the end. But first, let’s tackle some common hurdles you might face and how to overcome them.

Tackling Common Roadblocks in GitHub Java Projects & How to Fix Them

Working on GitHub Java projects often brings challenges—from handling complex codebases to fixing build errors or integrating external systems. Knowing how to address these issues can save time and keep your progress steady. With the right strategies and tools, you’ll overcome hurdles and build confidence with every project.

1. Problem: Large codebases can be overwhelming and hard to navigate.

Solution: Begin by carefully reading the README and any available documentation to understand the project’s purpose and structure. Use your IDE’s navigation tools like “Go to Definition” to follow how different parts of the code connect. 

Running the project in debug mode lets you step through the execution flow, making complex logic easier to grasp. Taking notes or drawing diagrams can help you visualize components and data flow, turning the enormous codebase into manageable sections.

2. Problem: Dependency or build errors prevent the project from compiling or running.

Solution: Check your build tool configurations (Maven’s pom.xml or Gradle’s build.gradle) to ensure all dependencies are correctly declared and compatible. 

Clear your build caches or force a fresh download of dependencies to avoid corrupted or outdated packages. Also, verify that your local Java version matches the one required by the project, as mismatched JDK versions often cause build failures.

Also Read: Exploring Java Architecture: A Guide to Java's Core, JVM and JDK Architecture

3. Problem: Poor or missing documentation makes understanding the code difficult.

Solution: Search for forks or similar projects with better documentation and code comments. Explore GitHub issues, pull requests, and discussion threads for explanations or clarifications shared by contributors. 

While reading, add your own inline comments to capture your understanding; this helps you while improving the project if you contribute your insights back.

4. Problem: Integrating databases and external APIs can be complex and error-prone.

Solution: Use tools like Postman or curl to test API endpoints independently, including adding request headers and handling API keys. Mock servers like Postman’s mock API or WireMock can simulate responses to debug tricky cases. 

For databases, verify connection strings, credentials, and drivers, and run simple test queries to confirm access before full integration.

5. Problem: Environment incompatibilities cause runtime errors or failures.

Solution: Use Docker or virtual machines to create a controlled environment matching the project’s requirements, which eliminates “works on my machine” issues. Ensure your JDK version, system PATH, and environment variables align with the project specs. 

This setup provides consistency across different machines and helps avoid many common environment-related problems.

Now comes the question of choosing the right project for you. Let’s see what considerations you need when picking the GitHub Java projects. 

How to Pick the Perfect GitHub Java Project for You?

Choosing a project depends on where you are in your learning journey and what skills you want to build. Ask yourself:

• What Java concepts am I confident in? (OOP, multithreading, networking?)
• Do I want to focus on desktop apps, web apps, or backend services?
• Am I looking to improve database handling, API integration, or UI design?
• How much time can I dedicate? Simple projects take less time, but advanced ones build deeper skills.
• Do I want to contribute to open-source or just study existing projects?

Evaluating your current strengths and goals will help you select projects that challenge you just enough to learn without overwhelming you. 

Here’s a detailed guide on selecting the right GitHub projects for you. 

Note: Always check project licenses (MIT, GPL, Apache, etc.) before forking or modifying code, especially if you plan to reuse it in portfolios or commercial projects.

Keeping these points in mind will help you make the most of your learning journey. Now, let’s explore how upGrad can help you take your Java skills further.

Take Your Java Skills to the Next Level with upGrad!

Working on these open-source GitHub Java projects is an effective way to boost your Java skills. These projects range from beginner-friendly applications like calculators to complex systems such as banking APIs, offering real coding experience and exposure to different programming styles. To make the most of these projects, start small, progressively challenge yourself, and focus on the skills you want to build.

However, many developers struggle to translate their passion into a structured learning path or a job-ready skill set. If you want a more guided approach or to accelerate your career growth, upGrad’s Software Development Courses deliver hands-on projects, personalized mentorship, and flexible schedules. Whether you aim to specialize in Cyber Security, Full Stack, or Game Development, upGrad equips you with the practical skills needed to succeed.

Apart from the courses mentioned earlier, here are some additional upGrad programs that help fast-track your skills with hands-on projects and expert mentorship.

• Cloud Engineer Bootcamp
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References:
https://javarush.com/en/groups/posts/en.1903.top-5-java-projects-on-github
https://github.com/topics/java-project?l=java

Java Projects with Source Code:

1. Calculator App

2. To-Do List Manager

3. Simple Chat Application

4. Currency Converter

5. Student Management System

6. Inventory Management System

7. Online Voting System

8. Expense Tracker

9. Library Management System

10. Online Quiz Portal

11. Banking System API

12. E-Commerce Platform

13. Real-Time Chat Server

14. Healthcare Management System

15. Machine Learning Pipeline in Java