Qatar uses the Plaza Premium Saphire Lounge in Jakarta, which is used by all the other foreign airlines bar SkyTeam and JAL (who uses the Garuda Lounge). The oneworld website is notoriously unreliable for lounge information as a lot of information may not be listed or be correct.

Having said that, the lounge in CGK is nothing special but relatively clean. They've got shower facilities too, although nothing too fancy. The quality of the food spread they have is very questionable, though. There's three choices of alcohol last time I went - red, white, and beer.