creating a fullscreen desktop environment?

how to create a fullscreen application, with no window frame, to simulate a 'virtual desktop'? I would like to know if it's possible using java and Qt C++? and what are the开发者_运维技巧 syntaxe for doing such thing in both languages?

To show a Qt widget fullscreen:

#include <QtGui>
#include <QtCore>

int
main(int argc, char* argv[])
{
  QApplication app(argc, argv);
  QWidget widget;

  //widget.show();  
  widget.showFullScreen();

  app.exec();
  return 0;
}