String srt1 = "javax.swing.plaf.metal.MetalLookAndFeel";
  String srt2 = "javax.swing.plaf.nimbus.NimbusLookAndFeel";
  String srt3 = "com.sun.java.swing.plaf.windows.WindowsLookAndFeel";
  String srt4 = "com.sun.java.swing.plaf.windows.WindowsClassicLookAndFeel";
  String srt5 = "com.sun.java.swing.plaf.motif.MotifLookAndFeel";
  String srt6 = "com.sun.java.swing.plaf.gtk.GTKLookAndFeel";
...

try {
            UIManager.setLookAndFeel(srt1);
            SwingUtilities.updateComponentTreeUI(this);
        } catch (Exception e) {
            e.printStackTrace();
        }
        JFrame.setDefaultLookAndFeelDecorated(true);