jna getDesktop bringWindowToTop
SetForegroundWindow
   SwitchToThisWindow
   ShowWindow
   BringWindowToTop

import com.sun.jna.Native;
import com.sun.jna.platform.win32.WinDef.HWND;
import com.sun.jna.win32.W32APIOptions;

public class ToggleDesktop3 {
   public interface User32 extends W32APIOptions {
      public static final String SHELL_TRAY_WND = "Shell_TrayWnd";
      public static final int WM_COMMAND = 0x111;
      public static final int MIN_ALL = 0x1a3;
      public static final int MIN_ALL_UNDO = 0x1a0;

      User32 instance = (User32) Native.loadLibrary("user32", User32.class,
            DEFAULT_OPTIONS);

      HWND FindWindow(String winClass, String title);

      long SendMessageA(HWND hWnd, int msg, int num1, int num2);
   }

   public static void main(String[] args) {
      // get the taskbar's window handle
      HWND shellTrayHwnd = User32.instance.FindWindow(User32.SHELL_TRAY_WND,
            null);

      // use it to minimize all windows
      User32.instance.SendMessageA(shellTrayHwnd, User32.WM_COMMAND,
            User32.MIN_ALL, 0);

      // sleep for 3 seconds
      try {
         Thread.sleep(3000);
      } catch (InterruptedException e) {
      }

      // then restore previously minimized windows
      User32.instance.SendMessageA(shellTrayHwnd, User32.WM_COMMAND,
            User32.MIN_ALL_UNDO, 0);
   }
}