code: @Nonnegative
    public static int getUTF8ByteCount (@Nullable final char [] aChars)
    {
      int nCount = 0;
      if (aChars != null)
        for (final char c : aChars)
          nCount += getUTF8ByteCount (c);
      return nCount;
    }
docs: Get the number of bytes necessary to represent the passed char array as an
  UTF-8 string.
  
  @param aChars
  The characters to count the length. May be <code>null</code> or
  empty.
  @return A non-negative value.