code: public static boolean setDockIcon(final Image icon) {
          try {
              final Class<?> clazz = Class.forName("com.apple.eawt.Application");
              final Method am = clazz.getMethod("getApplication");
              final Object app = am.invoke(null, new Object[0]);
              final Method si = clazz.getMethod("setDockIconImage", 
                                                new Class[] { Image.class });
              
              si.invoke(app, new Object[] { icon });
  
              return true;
          } catch (Exception e) {
              e.printStackTrace();
          } // end of catch
  
          return false;
      }
docs: Sets |icon| for Mac OS X dock.
  @return true if set