I’m looking for a reliable Java UML generator that can reverse-engineer my source code into a class diagram showing an overview of all class and package relationships. I don’t need it to decompile JARs since I already have the source code.
Most tools I’ve tried (like StarUML, ArgoUML, UModel, and MS Visio) either generate only individual class diagrams or are too unstable or hard to use. I’d prefer a tool that integrates well with Eclipse and can help me understand and document my current architecture better. Are there any good alternatives you’d recommend for this?
I’ve worked with Java projects for years, mostly inside Eclipse, and for anyone who wants a quick, no-fuss solution to visualize class relationships, I always recommend ObjectAid UML Explorer.
If you’re already using Eclipse, ObjectAid is probably the most seamless Java UML generator you’ll find. It’s lightweight, fast, and integrates right into your IDE. Just drag and drop classes from the Package Explorer, and it instantly shows inheritance, associations, and interfaces—live and in sync with your code.
Why I keep going back to it:
- Doesn’t overwhelm you with features you don’t need.
- Perfect for rapid visual inspection.
- Free for basic class diagrams, which is enough for many devs.
Heads-up though: if you need sequence or use-case diagrams, you’ll have to explore their paid extensions. But for a quick and intuitive view of class structures, ObjectAid is hard to beat.
Building on what @ishrth_fathima mentioned—ObjectAid is great inside Eclipse—but I’ve found something even more flexible if you want diagrams that live alongside your code.
If you’re leaning towards automation and documentation, combining PlantUML with the plantuml-class-diagram-generator is a solid approach. This combo is a powerful Java UML generator setup that scans your Java source and spits out clean PlantUML markup. From there, you can render diagrams in IntelliJ, Eclipse, VS Code—or even integrate them into CI pipelines.
Here’s what makes it even more valuable:
- Fully text-based—easy to diff, version, and review in pull requests.
- Perfect for wikis, Markdown docs, and developer onboarding.
- Keeps your diagrams in sync with your code with almost no manual effort.
So if you’re someone who loves automating doc generation and keeping everything under source control, this method scales really well for growing teams and codebases.
I’ve explored both ObjectAid and PlantUML workflows, and they’re fantastic. But if you’re looking for something truly comprehensive—something that offers architectural modeling too—Visual Paradigm might be what you need.
Visual Paradigm is a powerful standalone Java UML generator that reverse-engineers your entire Java project into rich UML class diagrams. It gives you a complete overview—classes, interfaces, packages, dependencies—all mapped out with precision.
What I personally find useful:
- Great for deep dives into legacy codebases.
- Supports bidirectional sync—update your diagram or update your code, and both stay in sync.
- Includes other UML views (like use-case, activity, and sequence diagrams) for full design workflows.
It’s definitely heavier and has a steeper learning curve, and yes—the best features are locked behind a paywall. But if you’re building serious documentation or modeling complex systems, this is one of the most full-featured tools available.