[cidd]

In Indonesia, many Javanese people traditionally have only one name. When they migrate to countries like Singapore, where a surname is required, they often use their given name as both their first and last name. As a result, you may see names such as Chandra Chandra or Supardi Supardi.

[ricudis]

Nowadays the Indonesian law requires at least two words for the person's full name, and the full name is regarded as a single entity no matter how many words it contains. Older generations of Javanese, having only a single name, usually duplicate it - I have seen such duplicate names in official Indonesian documents.

[toast0]

Or you get something like Someone FNU. Where FNU at some point meant 'first name unknown', but is now the person's last name at least in the people I've known... But I see references to it ending up as their firstname, so FNU Someone, which would make a little more sense, but is still pretty bizarre. Someone Someone seems like the best way to handle it, assuming single names aren't allowed (because yeah)