throws Throwable
  public boolean uasort(Env env,                        ArrayValue array,                        Callback func,                        @Optional long sortFlag)    throws Throwable  {    if (array == null)      return false;    if (!func.isValid()) {      env.warning(L.l("Invalid comparison function"));      return false;    }    array.sort(new CompareCallBack(ArrayValue.GET_VALUE, SORT_NORMAL, func,                                   env), NO_KEY_RESET, NOT_STRICT);    return true;  }