static <T> T getStyleFromTableUI( Component c, Function<FlatTableUI, T> f ) {
		JTable table = (JTable) SwingUtilities.getAncestorOfClass( JTable.class, c );
		if( table != null ) {
			TableUI ui = table.getUI();
			if( ui instanceof FlatTableUI )
				return f.apply( (FlatTableUI) ui );
		}
		return null;
	}
Because this border is always shared for all tables,
get border specific style from FlatTableUI.
flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatTableCellBorder.java