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A desktop application for fast UML diagramming.

Guide for JetUML Developers


System Requirements

The current version of JetUML is built with Java 21, the latest long-term support (LTS) release. To build JetUML, it is necessary to have the Java Development Kit version 21 and the jar files of JavaFX version 21 available. The JetUML code base is configured to build easily with Eclipse, but use of this IDE is optional. To contribute code, it will be necessary to run the Checkstyle tool.

Building the Application in Eclipse

  1. Ensure that you meet the system requirements, including a working version of Eclipse.
  2. In Eclipse, ensure that the JDK 21 is the default workspace JRE (_Window Preferences Java Installed JREs_).
  3. Create a new user library called JavaFX that includes all the JavaFX 21 jar files. To create this library, access _Window Preferences Java User Libraries_, select New…, enter the exact string JavaFX. Then, select this library, and click Add External JARS…, then find and select the jar files under the lib directory of your JavaFX download.
  4. Import the JetUML repo in Eclipse (_File Import Git Projects from Git Clone URI_). If you meet the system requirements, the project should build automatically.
  5. To run JetUML, right-click on the project in the Package Explorer and select _Run As Java Application_, selecting JetUML as the main file.
  6. If you are using a Mac, to run the application, open the run configuration and make sure the checkbox “Use the -XstartOnFirstThread argument when launching with SWT” is not checked.

Committing Code

  1. All committed code must respect all the JetUML style guidelines. These are available as a style file for the Checkstyle Eclipse Plug-in. Before committing code for JetUML, make sure to install the plug-in, activate it, and check for any warning.
  2. All commits must be associated with an issues using an issue tag as the first token in the commit comment, using the format [$NB] where NB is the issue number. For example, [#519] Add constraint for connection to notes.
  3. Ensure that any new file includes the copyright notice.
  4. Ensure that all unit test pass.

Packaging the Application

JetUML can be packaged as a self-contained application for Windows, Linux, and possibly Mac. This is done with the jpackage tool distributed with OpenJDK.


Run this from the git repo root (where FXMODS points to the JavaFX mods directory, e.g.,):

set FXMODS="C:\local\Java\javafx-jmods-21.0.2"
jpackage --module-path %FXMODS%;bin\jetuml --add-modules jetuml --module jetuml/org.jetuml.JetUML --app-version 3.6 --icon docs\JetUML.ico --win-shortcut --win-dir-chooser


Run this from the git repo root (adjust paths as needed):

jpackage --module-path $JMODS:$FXMODS:bin/jetuml --add-modules jetuml --module jetuml/org.jetuml.JetUML --app-version 3.7 --icon icons/jet.png 


Run this from the git repo root (where PATH_TO_FX_MODS points to the JavaFX mods directory)

$JAVA_HOME/bin/jpackage -n JetUML --module-path $PATH_TO_FX_MODS:bin/jetuml --add-modules jetuml --module jetuml/org.jetuml.JetUML --app-version 3.4 --module jetuml/org.jetuml.JetUML --type pkg --icon docs/JetUML.icns

To be used in the Eclipse copyright tool.

JetUML - A desktop application for fast UML diagramming.

Copyright (C) ${date} by McGill University.

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see

See Also