Looking for a good free UML2 modelling editor …

I was using Poseidon as a modelling editor for my UML2 diagrams. It was based on Java and I was able to run it from both GNU/Linux and MS-Windows. It was not free software but the Community Edition was free (as in “free beer”) and has all the tools I modestly needed. The only trick: all the diagrams had a string in the bottom, stating it was not meant to be used for commercial purpose (for educational purpose, I’ve written a small software that removes it).

Today, Gentleware boss announced that Poseidon will go away. He said it will be replaced by Apollo for Eclipse and by a new licensing model (renting) starting at 5€ per month. An unregistered version will be available but it won’t be possible to export, print, save, etc.

First, this shows one of the problems of using free-as-in-free-beer-but-proprietary software (and not really free software): the owner can change the licence, the software availability and usage conditions at any time. Secondly, althought I understand the move from a commercial/business point of view (if they need money) but I wonder if they are not depriving themselves from a potential user base (Community Edition users that will recommend paid version in a professional environment).

Anyway, I am now looking for a new, good and free UML2 modelling editor. After a quick search, I’ve found:

  • ArgoUML, a Java-based editor supporting UML1.4, able to import/export Java code (*) (BSD licence)
  • Umbrello UML Modeller, written for KDE only, it can import/generate code from/for Python, Java, C++, … (GPL)
  • BOUML is also Java-based and I think it’s the only one in this list that supports UML2 ; it can generate code for C++, Java (and Idl) (GPL)
  • PyUT is a class diagram editor written in Python and supports UML1.3 ; it can import/export Python and Java source code and export C++ code (GPL)

I really don’t have time for the moment to test all these software. As soon as I’ll have time, I’ll give them a try. Meanwhile, if you have other suggestions and/or any experience with one of them, please feel free to post a comment.

(*) Although I am not confortable with code auto-generation tools, the ability to import/generate code for a programming language is a good indication of the ability of the modelling tool to understand and take into account this language specificity. You don’t want Java syntax highlights when developping a Python application.