Altova UModel vs Violet UML Editor

Altova UModel has no write-up on Specifiction yet; its figures are above.

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.