JScrollPane is not appeared.

Question

Hi,
I want to use JScrollPane.
However in my program scrollbar is not appeared.
What is wrong?
Thanks.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ImageViewFrame extends JFrame {
public static void main(String[] args) {
     ImageViewFrame frame = new ImageViewFrame();
     frame.show();
ImageViewFrame() {
     setSize(300, 300);
     addWindowListener(new WindowAdapter() {
          public void windowClosing(WindowEvent evt) {
          System.exit(0);
     JPanel panel = new JPanel();
     panel.setSize(1000, 1000);
     JScrollPane scrollPane = new JScrollPane(panel);
     getContentPane().add(scrollPane, BorderLayout.CENTER);

Answer 1

I add a line, "panel.setPreferredSize(new Dimension(1000, 1000));"
It works well.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ImageViewFrame extends JFrame {
public static void main(String[] args) {
     ImageViewFrame frame = new ImageViewFrame();
     frame.show();
ImageViewFrame() {
     setSize(300, 300);
     addWindowListener(new WindowAdapter() {
          public void windowClosing(WindowEvent evt) {
          System.exit(0);
     JPanel panel = new JPanel();
     panel.setSize(1000, 1000);
     panel.setPreferredSize(new Dimension(1000, 1000));
     JScrollPane scrollPane = new JScrollPane(panel);
     getContentPane().add(scrollPane, BorderLayout.CENTER);