getDefault().getDescriptor().getInstallURL();



public static ImageDescriptor getImageDescriptor(String name) {
   String iconPath = "icons/";
   try {
       URL installURL = getDefault().getDescriptor().getInstallURL();
       URL url = new URL(installURL, iconPath + name);
       return ImageDescriptor.createFromURL(url);
   } catch (MalformedURLException e) {
       // should not happen
       return ImageDescriptor.getMissingImageDescriptor();
   }
}