code: public String fill(Object... fill) {
                  for (int i = 0; i < fill.length; ++i) {
                          str = str.replace("{" + i + "}", fill[i].toString());
                  }
                  return str;
          }
docs: fill the string like <code>My name is {0}, I'm {1} years old</code>
  with given objects.<br>
  
  @param fill fill object
  @return formated string