Here you can find the source of setLookAndFeel()
public static void setLookAndFeel()
//package com.java2s; /*************************************************************************** This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License 3 as published by the Free Software Foundation./* w w w . j ava 2s.c om*/ This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. ***************************************************************************/ import javax.swing.*; public class Main { public static void setLookAndFeel() { 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(); } } }