code: public byte set(int index, byte e) {
      rangeCheck(index);
      byte value = elements[index];
      elements[index] = e;
      return value;
    }
docs: Sets an element of this array.
  
  @param index
  The index of the element to set.
  @param e
  The value of the element.
  @return The value previously stored at the specified index.
  @throws IndexOutOfBoundsException
  if <code>index &lt; 0 || index &gt;= size()</code>.