Version:           3.0.0a4 (using KDE KDE 3.1)
Installed from:    RedHat RPMs
Compiler:          g++ (GCC) 3.2.2 20030222 (Red Hat Linux 3.2.2-5) 
OS:          Linux

I create a new Java Application project.  The project is created ok, and the Main.java file exists.  Then I try to create a new Java file (both File->New and "New File" (side bar button) -> Java Source).  The New File dialog comes up with "Java source (.java)" as the type and "Add to project" checked.  I enter the file name and click OK.  No errors are given in the GUI, but the following error is reported from the console:

QObject::connect: No such slot JavaSupportPart::configWidget(KDialogBase*)
QObject::connect:  (sender name:   'unnamed')
QObject::connect:  (receiver name: 'JavaSupportPart')

I built Gideon from source, and haven't had any problems with C++ projects.  The only configuration changes I've made from the defaults are to syntax highlighting colors.