Java. Проблема с анимацией (gif).

Анимация очень быстрая. Смотрел в браузере и в приложении "фотографии" windows 10 гораздо медленей анимация.
код:
package org.alauncher.minecraftlauncher.rmo;

import java.awt.Dimension;
import java.awt.Toolkit;
import java.net.URL;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JWindow;
import javax.swing.SwingConstants;

public class Bootstrapper extends JWindow {
public static Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
public static int sizeWidth = 240;
public static int sizeHeight = 114;
public static int locationX = (screenSize.width - sizeWidth) / 2;
public static int locationY = (screenSize.height - sizeHeight) / 2;
public static void main(String[] args)
{
JWindow window = new JWindow();
URL imgURL = Bootstrapper.class.getResource("alauncher.gif");
window.getContentPane().add(new JLabel("", new ImageIcon(imgURL), SwingConstants.CENTER));
window.setBounds(locationX, locationY, sizeWidth, sizeHeight);
window.setVisible(true);
try
{
Thread.sleep(5000);

}
catch(Exception exec)
{

}
window.dispose();
}
}