JScrollPane will not appear

Question

I'm trying to add a scroll bar to a JTextArea. The textarea appears but there is no scroll bar.
Here's what I'm doing. I've included the whole class in case there is something relevant that I don't realise. Any ideas on what I'm doing wrong?
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Basic extends JFrame
JTextArea output;
     public Basic()
          super( "Diagram" );
          setSize( 800, 600 );
          Container c = getContentPane();
          JMenuBar bar = new JMenuBar();          
          JMenu fileMenu = new JMenu( "File" );
          JMenuItem n = new JMenuItem( "New" );
          JMenuItem open = new JMenuItem( "Open" );
          JMenuItem close = new JMenuItem( "Close" );
          JMenuItem save = new JMenuItem( "Save" );
          JMenuItem create = new JMenuItem( "Create Diagram" );     
          fileMenu.add(n);
          fileMenu.add(open);
          fileMenu.add(close);
          fileMenu.add(save);
          fileMenu.add(create);
          bar.add(fileMenu);
          output = new JTextArea();
          JScrollPane scroll = new JScrollPane(output);
          n.addActionListener(
               new ActionListener()
               {public void actionPerformed( ActionEvent e)
                    OpenUI o = new OpenUI();
                    TokenTest t = new TokenTest(o.fileText, output);
          c.add(bar, BorderLayout.NORTH);
          c.add(scroll);
          show();          
}

Answer 1

Use the methods SetVerticalScrollbarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS) and
SetHorizontalScrollbarPolicy(HORIZONTAl_SCROLLBAR_ALWAYS) so the scrollbars will appear whether they are needed or not.
OR
use new JTextArea(40,100) to set the minimum rows and columns of the textarea.