Support for locales with no 639-1 code

Looking at the Java spec for locales,it would seem possible to support languages for which there exists only an ISO 639-2 code (three letters).

Right now it seems DHIS2 is using the I SO 639-1 codes. Some languages do not have this code but do have a 639-2 code.

Any thoughts on if this would be possible?

Best regards,

Jason