New to Java

I am trying to play a video in java, and I have used code from some tutorials, and in the sample code it uses a jfilechooser to select a file, and then play it in a jframe, like so...

JFrame mediaTest = new JFrame( "Media Tester" );
            mediaTest.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
            
            MediaPanel mediaPanel = new MediaPanel( mediaURL );
            mediaTest.add( mediaPanel );
            
            mediaTest.setSize( 300, 300 );
            mediaTest.setVisible( true );

what I am trying to do is create a jframe that is tabbed. one of these tabs has a jinternalframe located in it. so i modified the code to play in the jinternalframe. However, i get sound except no video. possibly the jinternalframe doesn't have the same usage as a jframe?

// JFrame mediaTest = new JFrame( "Media Tester" );
              //  mediaTest.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
                
                MediaPanel mediaPanel = new MediaPanel( mediaURL );
            
                newUI.frmScreen.add( mediaPanel );
                
                newUI.frmScreen.setSize( 300, 300 );
                newUI.frmScreen.setVisible( true );

any help is appreciated.
thanks.