question: private void showNotificationLabel ( String i18nKey , Object ... arguments ) { upperPanel . setVisible ( false ) ; collapsibleErrorTable . setVisible ( false ) ; GridBagConstraints constraint = new GridBagConstraints ( ) ; constraint . fill = GridBagConstraints . BOTH ; constraint . weightx = 1.0 ; constraint . weighty = 1.0 ; centerPanel . removeAll ( ) ; centerPanel . add ( new JPanel ( ) , constraint ) ; constraint . weightx = 0.0 ; constraint . weighty = 0.0 ; constraint . fill = GridBagConstraints . NONE ; constraint . anchor = GridBagConstraints . CENTER ; centerPanel . add ( new ResourceLabel ( i18nKey , arguments ) , constraint ) ; constraint . weightx = 1.0 ; constraint . weighty = 1.0 ; constraint . fill = GridBagConstraints . BOTH ; centerPanel . add ( new JPanel ( ) , constraint ) ; centerPanel . revalidate ( ) ; centerPanel . repaint ( ) ; }
target:  Shows a central label displaying a notification to the user (e.g. for errors or during loading).