code: protected void setValue(int index, int value) {
          DateTimeField field = getField(index);
          int[] values = field.set(this, index, iValues, value);
          System.arraycopy(values, 0, iValues, 0, iValues.length);
      }
docs: Sets the value of the field at the specified index.
  <p>
  In version 2.0 and later, this method copies the array into the original.
  This is because the instance variable has been changed to be final to satisfy the Java Memory Model.
  This only impacts subclasses that are mutable.
  
  @param index  the index
  @param value  the value to set
  @throws IndexOutOfBoundsException if the index is invalid