結構使いそうなのでメモ書きしておきます。
import javax.swing.UIManager;
void setLAF() {
try {
System.out.println(UIManager.getSystemLookAndFeelClassName());
// UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
// javax.swing.plaf.metal.MetalLookAndFeel
// com.sun.java.swing.plaf.gtk.GTKLookAndFeel
// com.sun.java.swing.plaf.motif.MotifLookAndFeel
// com.sun.java.swing.plaf.windows.WindowsLookAndFeel
} catch (Exception e) {
e.printStackTrace();
}
}