Simple question I think, add JPanel to JScrollPane

Question

I would imagine that for anyone with experience with Java this will be a simple problem. Why can't I add a JPanel to a JScrollPane using myScrollPane.Add(myPanel); ?? it seems to get hidden...
This works correctly:
     //Create a panel
     JPanel panel = new JPanel(new FlowLayout());
     //Make it pink
     panel.setBackground(Color.pink);
     //Make it 400,400
     panel.setPreferredSize(new Dimension(400,400));
     //Create a Scrollpane
     JScrollPane scrollPane = new JScrollPane(panel);
     //Make it 300,300
     scrollPane.setPreferredSize(new Dimension(300,300));
     //Create a JFrame
     JFrame frame = new JFrame("Test Scrollpane");
     frame.setLayout(new FlowLayout());
     //Set close operation
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     //Set its size
     frame.setSize(600,600);
     //Add Scrollpane to JFrame
     frame.add(scrollPane);
     //Show it
     frame.setVisible(true);
This doesnt:
     //Create a panel
     JPanel panel = new JPanel(new FlowLayout());
     //Make it pink
     panel.setBackground(Color.pink);
     //Make it 400,400
     panel.setPreferredSize(new Dimension(400,400));
     //Create a Scrollpane
     JScrollPane scrollPane = new JScrollPane();
     scrollPane.add(panel);
     //Make it 300,300
     scrollPane.setPreferredSize(new Dimension(300,300));
     //Create a JFrame
     JFrame frame = new JFrame("Test Scrollpane");
     frame.setLayout(new FlowLayout());
     //Set close operation
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     //Set its size
     frame.setSize(600,600);
     //Add Scrollpane to JFrame
     frame.add(scrollPane);
     //Show it
     frame.setVisible(true);

Answer 1

rcfearn wrote:
I would appreciate it you could read the sample code, I am asking the question as to why I have to do this? For structural reasons I don't want to have to add the JPanel during instatiation of the JScrollPane...Please read the [jscrollpane api.|http://java.sun.com/javase/6/docs/api/javax/swing/JScrollPane.html] To display something in a scroll pane you need to add it not to the scroll pane but to its viewport. If you add the component in the scroll pane's constructor, then it will be automatically added to the viewport. if you don't and add the component later, then you must go out of your way to be sure that it is added to the viewport with:
JScrollPane myScrollPane = new JScrollPane();
myScrollPane.getViewport().add(myComponent);