According to the API, the SplashScreen is closed automatically as soon as the first window is displayed by Swing/AWT. In Mustang build 42 this is not the case (testet on Solaris 9/sparc).

How to reproduce:
$ java -fullversion
java full version "1.6.0-ea-b42"
$ cat Splash.java
import java.awt.*;

public class Splash {
    
    static {
        try {
            Thread.sleep(5000);
        } catch (Exception e) {}
    }
    
    public static void main(String[] args) {
        Frame f = new Frame("Frame");
        f.setSize(200, 200);
        f.setVisible(true);
    }
}
$ javac Splash.java
$ java -splash:duke.gif Splash

=> The Splash comes up, but it stays on the screen, even if the Frame is visible already.

###@###.### 2005-07-14 14:46:46 GMT