package musicplayer;import javax.swing.UIManager;import java.awt.*;public class MusicPlayer {  boolean packFrame = false;  public MusicPlayer() {    MusicFrame frame = new MusicFrame();    frame.validate();    Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();    Dimension frameSize = frame.getSize();    if (frameSize.height > screenSize.height) {      frameSize.height = screenSize.height;    }    if (frameSize.width > screenSize.width) {      frameSize.width = screenSize.width;    }    frame.setLocation((screenSize.width - frameSize.width) / 2,                     (screenSize.height - frameSize.height) / 2);    frame.setVisible(true);  }  public static void main(String[] args) {    new MusicPlayer();  }}