docs: public static boolean isAnonymous(String className) {
          int i = className.lastIndexOf('$');
          if (i >= 0 && ++i < className.length()) {
              while(i < className.length()) {
                  if(!Character.isDigit(className.charAt(i))) {
                      return false;
                  }
                  i++;
              }
              return true;
          }
          return false;
      }