Re: why isnt this scroll panel scrolling?

heres my class file. All I am trying to do is get the scroll panel to
have a scroll bar and the ability to scroll.

Why does changing the size of the JScrollPane have no affect on it when
I run the program? What do I have to do to gain scrolling
capabilities?

Thanks

package orthopedicnotegenerator;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.font.*;
import java.text.Collator;
import javax.swing.event.*;
import java.util.Date;
import java.text.DateFormat;

class ExamKnee2 extends JDialog{

  final int WIDTH = 830;

  AccessConnection dataConnection = new AccessConnection();

  JPanel pane;
  JScrollPane scroller;

  public ExamKnee2() {

    setModal(true);
    Container pane = this.getContentPane();
    this.setAlwaysOnTop(true);

    pane.setLayout(new BorderLayout());
    //pane.setLayout(null);

    setDefaultCloseOperation(DISPOSE_ON_CLOSE);
    setBounds(300,0,WIDTH,400);

    addWidgets();

    setVisible(true);
    validate();

  }

  public void addWidgets(){

    pane = new JPanel();
    pane.setLayout(new BorderLayout());

    JButton button = new JButton("Button 1 (PAGE_START)");
    pane.add(button, BorderLayout.PAGE_START);

    button = new JButton("Button 2 (CENTER)");
    button.setPreferredSize(new Dimension(200, 100));
    pane.add(button, BorderLayout.CENTER);

    button = new JButton("Button 3 (LINE_START)");
    pane.add(button, BorderLayout.LINE_START);

    button = new JButton("Long-Named Button 4 (PAGE_END)");
    pane.add(button, BorderLayout.PAGE_END);

    button = new JButton("5 (LINE_END)");
    pane.add(button, BorderLayout.LINE_END);

    scroller = new JScrollPane(pane);
    scroller.setSize(200,200);
    add(scroller, BorderLayout.CENTER);

  }

  public static void main(String args[]){
    ExamKnee2 examKnee =
        new ExamKnee2("Right", "123-45-6789", "2 weeks");

  }
}