How to enable JFormDeveloper SWING source generation into java source

JFormDeveloper is quite handy tool of Intellij IDEA. The additional source code for the UI design that you do by default it generated into the *.class files. This might not be so useful for the project setup, for example if you use maven as a build tool. So what you need is to tell Intellij that the extra code generated by the JFormDeveloper needs to go into your *.java files.

You can do this by setting this from preference panel: Preferences, search "Gui", GUI Designer