public void themeChanged(){
synchronized (sun.awt.UNIXToolkit.GTK_LOCK) {
    native_switch_theme();
  }
  cache.flush();
}

public void themeChanged ( ) { synchronized ( sun . awt . UNIXToolkit . GTK_LOCK ) { native_switch_theme ( ) ; } cache . flush ( ) ; }
notify native layer of theme change , and flush cache
