code: public JsonArray set(int index, int value) {
      values.set(index, Json.value(value));
      return this;
    }
docs: Replaces the element at the specified position in this array with the JSON representation of
  the specified <code>int</code> value.
  
  @param index
  the index of the array element to replace
  @param value
  the value to be stored at the specified array position
  @return the array itself, to enable method chaining
  @throws IndexOutOfBoundsException
  if the index is out of range, i.e. <code>index &lt; 0</code> or
  <code>index &gt;= size</code>