BOUML vs Violet UML Editor

BOUML is a free UML 2 toolbox for modeling systems and generating code, available as desktop software for Linux, macOS, and Windows. It supports use case, sequence, communication, class, composite class, activity, state, object, composite object, component, and deployment diagrams. Built-in generators cover C++, C, Java, PHP, Python, IDL, and MySQL; reverse-engineering tools are listed for C++, Java, PHP, and MySQL, and round-trip tools for C++, Java, and PHP. Plug-outs provide XMI 1.2 and 2.1 generation, XMI 2.1 import, and Rational Rose model import. External plug-outs can be written in C++ or Java and run separately from BOUML. An HTML documentation generator can output diagrams as PNG or SVG. Project control and synchronization tools support work by several people. The maker says it can handle several thousand classes while using little memory. Version 7.11 is identified as the final release, with patch 4 listed for some distributions. Releases since version 7.0 are free to use; the maker states they come without warranty.

Violet UML Editor is a free, open-source application for drawing simple UML diagrams quickly. It supports class, activity, object, sequence, state and use case diagrams. The project describes Violet as easy to learn and use, and intended for developers, students, teachers and authors who need straightforward UML diagrams. Violet is licensed under GNU General Public License version 2.0 (GPLv2) and is written in Java, with Java Swing and Java SWT listed as interfaces. Linux, Mac and Windows are named operating systems, while the platform listing also includes web. The source repository directs users to SourceForge for downloads. Building from source requires Java Development Kit 17 or greater and Maven 3 or greater; the repository specifies running `mvn clean package` from the root directory to compile and package the project. The maintainer invites contributors to submit pull requests and says requests will be examined before contacting contributors. Violet has one listed plan: free, described as a completely free, cross-platform UML editor. Deployment is listed as both, with web, Windows and Linux among supported platforms.