There is more than one artist with this name:

1) Nyoman Oka Antara (born 8 July 1981) is an Indonesian rapper and actor of Balinese descent.
2) Oka, a band from the Sunshine Coast north of Brisbane, Australia.
3) OKA is also a pop group from Finland. Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.