The following code:

public class Temp {
    public static void main(String[] args) {
        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        GraphicsDevice[] devices = ge.getScreenDevices();
        for (GraphicsDevice device : devices) {
            Frame w = new Frame();
            //w.setBackground(Color.BLACK);
            device.setFullScreenWindow(w);
        }
    }
}

throws NPE on JDK7 b57 like the following:

Exception in thread "main" java.lang.NullPointerException
at java.awt.GraphicsDevice.setFullScreenWindow(GraphicsDevice.java:285)
at sun.awt.Win32GraphicsDevice.setFullScreenWindow(Win32GraphicsDevice.java:365)
at shapedtrans.Temp.main(Temp.java:12)
        ...

Code sample works for JDK6