import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Main {
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setSize(300, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setTitle("System LAF Demo");
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (UnsupportedLookAndFeelException e) {
e.printStackTrace();
}
SwingUtilities.updateComponentTreeUI(frame);
frame.setVisible(true);
}
}