Bug Gym is an offline Java practice desktop app that simulates Moodle-style exam questions with syntax highlighting, automated tests, and beginner-friendly progression. No login, No internet required, no complex IDE setup, just focused learning.
Windows • macOS • Linux
- Open the Releases page for this repository.
- Download the installer or archive for your operating system.
- Install or extract, then launch the application.
Bug Gym is an open-source project without paid code-signing certificates. Your OS may show warnings:
- macOS: Right-click → Open, then confirm
- Windows: Click "More Info" → "Run Anyway"
If you downloaded from the official GitHub Releases page, it's safe.
At KMUTT's School of Information Technology (SIT), students take Java programming exams through Moodle:
- Moodle is locked to exam time — no official practice questions
- Moodle editor = plain text box (no highlighting, no line numbers)
- jGRASP lets you write code but gives you zero questions to solve
- LeetCode / HackerRank feel impossible for beginners (too many concepts at once)
- Beginners need structured, exam-like practice — but most options are either too basic (just syntax) or way too hard
Bug Gym gives you that missing bridge: realistic practice in a safe, offline space.
Built for exam practice - Simulates Moodle-style questions offline
Markdown problem descriptions - Clear, readable questions with hints
Automated test execution - Run tests immediately, see what's wrong
Offline-first - Practice anywhere without internet
Super beginner friendly - Questions start from "Hello World" level
Open Content Structure - All questions written in Markdown files (easy to add / modify via source)
Progress tracking - See what you've completed
Intentionally minimal feature set - Just code, test, learn
- Students learning Java in introductory CS courses
- Educators who want to create custom practice problems
- Self-learners who need structured practice without Moodle
- Schools that want an offline alternative for lab exercises
| Feature | Bug Gym | Moodle | jGRASP | LeetCode | VS Code |
|---|---|---|---|---|---|
| Syntax highlighting | ✅ | ❌ | ✅ | ✅ | ✅ |
| Offline practice | ✅ | ❌ | ✅ | ❌ | ✅ |
| Beginner problems | ✅ | Admin dependent | ❌ | Limited (mostly interview-level) | ❌ |
| Automated testing | ✅ | ✅ | ❌ | ✅ | Manual |
| Simple interface | ✅ | ✅ | ✅ | 🟨 | ❌ |
| Custom challenges | ✅ (Via Source) | Admin only | ❌ | ❌ | ❌ |
| Exam-style practice | ✅ | ✅ | ❌ | ❌ | ❌ |
Bug Gym = jGRASP's simplicity + Moodle's testing + beginner-friendly problem sets
- Java syntax highlighting using RichTextFX
- Line numbers for easy reference
- Keyboard shortcuts
- Markdown support with tables, code blocks, formatting
- Hint system to help when stuck
- Example inputs/outputs for clarity
- Automated compilation and execution
- Input/output comparison to show differences
- Clear error messages when tests fail
- Progress indicators showing what passed
- Dark/Light mode
- Adjustable font size
- Resizable layout
- Works offline (practice anywhere)
- Progress tracking
- Java 21+ (Download OpenJDK)
- Maven 3.8+ (Download Maven)
# Clone repository
git clone https://github.com/PhilixTheExplorer/bug-gym.git
cd bug-gym
# Run application
mvn clean javafx:run
# Build JAR
mvn clean package
# Output: target/bug-gym-1.0.0.jar
# Build native installer (requires platform-specific tools)
# See .github/workflows/release.yml for detailsBug Gym began as a personal project, a gift for someone special to make learning Java feel less scary, more fun, and a little bit magical.
It was built to turn confusion into confidence, and to show that sometimes the best help is a tool made just for them.
If it helps others along the way, that's even better.
- Java 21 - Modern Java features
- JavaFX 21 - Cross-platform desktop UI
- RichTextFX - Code editor with syntax highlighting
- CommonMark - Markdown parsing for problem descriptions
- jpackage - Native installers for each platform
- Maven - Build automation
- GitHub Actions - Automated releases
Bug Gym follows Semantic Versioning:
- MAJOR: Breaking changes
- MINOR: New features, backward compatible
- PATCH: Bug fixes
This project is licensed under the GNU General Public License v3.0.
You are free to use, modify, and distribute this software, but any modifications must also be open source under GPL v3.
See LICENSE for full details.
Contributions are welcome and should be small, focused, and well-tested. This project is primarily maintained as a learning and personal project.
- Fork the repository and create a feature branch
- Keep changes scoped to a single purpose
- Update or add tests when appropriate
- Open a pull request with a clear description of the change
See CONTRIBUTING.md for detailed guidelines.
- 🐛 Bug Reports: Open an issue
- 💡 Idea: Start a discussion
- ❓ Questions: Discussions Q&A
Built with:
- JavaFX - Application framework
- RichTextFX - Code editor component
- CommonMark Java - Markdown parsing
Inspired by the struggle of learning Java without the right tools.
Made with ❤️ for Java beginners everywhere
Especially for one person who inspired it all