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Posts tagged: Javeleon

JavaFX + ScenicView + Javeleon = LiveFX

JavaFx + ScenicView

JavaFx + ScenicView

  If you use JavaFX for development, normally you create applications with a GUI - so far so good. How often do you restart your application to check if a simple code change works? Many times?

If you develop a control, wouldn't it be great to see your code changes immediately?

We use Javeleon for application development together with JVx because it saves a lot of development time and creates live feeling. We thought that Javeleon could also be useful for JavaFX application or control development because application restarts always waste development time.

The integration of Javeleon in your JavaFX application is not difficult, simply add two VM arguments


to your launch/run configuration (use your directories). If you use Javeleon for development, it reduces application restarts to a bare minimum, but you should know the limits.

Javeleon reloads classes directly in your VM, but it does not recreate members of your loaded instances and does not call the constructor of your classes again.

You should use a Javeleon reload listener to trigger reload of resource files (css, xml) and call specific methods after reload e.g. call init again.

Imagine you have a GUI with a button and on click you start the creation of a report or execute some business logic, etc. If you change the source code for your button click action or change a method used in the action, your application always invokes the changed "code".

Sounds tricky? It isn't, but live coding is not well known.

If you are interested, simply try it out!

I'm not sure whether the current downloadable Javeleon 3.0 is up-to-date because I found some smaller problems with ScenicView. The problems were already fixed and hopefully released asap.
My working version number: Javeleon version 3.0.1 dev 2012-11-13 (r699).

If you have problems, simply contact the Javeleon team.

Javeleon Eclipse Plugin

If you use Javeleon for JVx applications and your preferred IDE is Eclipse, check out our new Eclipse plugin. It is the inofficial Javeleon plugin for Eclipse. The name of the plugin is Javilion Plugin. It is available on SourceForge and it is released under Apache License 2.0.

The plugin has two helpful features:

  • Reload Javeleon manually

    Simply reload Javeleon whenever you want.

  • Automatic Reload after resource file update

    The current Javeleon version(s) does not reload when you change a resource file like .properties, .xml, ... If you enable the Javilion plugin in your Eclipse project, reload happens automatically.

If you want to use the plugin, use the following instructions, because we have not setup an updatesite right now!

  • Download the plugin
  • Copy the jar to the dropins or plugins directory of your Eclipse installation
  • Restart Eclipse
  • Add Javilion nature to your project: right mouse click on your project, Javilion/Add nature
  • Right click on your project to verify that Javilion is added:

    Javilion Plugin

    Popup menu

  • Configure your application run configuration and add the port property to your javaagent, e.g.:


    The port 9999 is the default setting. If you need another port, configure it in your .project file:


    It is a little bit tricky, because we don't have a configuration UI for the plugin right now.

If you use the plugin together with a Javeleon ReloadListener (-Djaveleon.reload.listener=app.MyListener), you feel the full power of Javeleon.

Application development without restarts

Some months ago, I read an interesting article about Javeleon. I thought it would be very useful for JVx developers because it is possible to start an application, modify screens and lifecycle objects and use the new instances live in the application without restarting it. It could save a lot of development time. Use the JRebel ROI calculator to see what you can save - It is amazing.

The integration of Javeleon in the JVx development process is very simple. Go to the Javeleon Download Page and download the standalone version 1.5 or 2.0 beta. It is not necessary to add javeleon.jar to the classpath of your application. If you use Eclipse, open the Run configuration dialog and add the following VM arguments:\temp\java

If you use version 1.5 and version 2.0 for your tests, be sure that you delete the D:\temp\java\JaveleonBoot directory. Otherwise you get JVM startup Exceptions.

After the first start, watch the Java Console view because Javeleon is disabled until you request and download a license. Don't be affraid because the license is used to keep track of how many users Javeleon has. Details about the license are available here. With a valid license, it is possible to start development.

If everything is setup correctly, start your application and open a work-screen. Go back to Eclipse and modify the source-code of your work-screen, e.g. change the Layout, change the text of a Label or change some properties of a DBStorage. Be sure that your source is compiled (should be the default Eclipse setting) before you go back to your application. To see the changes in your application, simply close and open the modified work-screen.
You save the time to restart your application and perform a login. The MetaData cache also saves some seconds.

One negative point is that you need JVx as project dependency instead of the jar version.


It is possible to use Javeleon without JVx project dependency. Simply unzip jvx.jar and add the created folder (class folder) to your classpath. It is not possible to compile JVx!

Update [2]

With the current Javeleon beta release of today (Jan. 17) - version 2.0.3 - it is possible to use jar files too. Now the integration of Javeleon works perfect.

Thanks to Allan Gregersen and the Javeleon Team for the support.