The specs states:
"SplashScreen.getSplashScreen() returns [...] null if [...] it has already been closed"
"The [splash screen] window is closed automatically as soon as the first window is displayed by Swing/AWT"

And the following test fails:

    public void testAutoClose() {
        SplashScreen ss = SplashScreen.getSplashScreen();
        Frame frame = new Frame();
        assertTrue(ss.isVisible());
        assertNotNull(SplashScreen.getSplashScreen());

        frame.setVisible(true);
        
        assertFalse(ss.isVisible());
        // Fails here
        assertNull(SplashScreen.getSplashScreen());

        frame.dispose();
    }