Well, technically it hasn't, since Timor-Leste split off in 2002. And there have been and remain separatist tendencies of various strengths in Papua, Aceh, Ma

Well, technically it hasn't, since Timor-Leste split off in 2002. And there have been and remain separatist tendencies of various strengths in Papua, Aceh, Maluku, etc. What has held Indonesia together is the overwhelming dominance of the Javanese, through a combination of (comparative) economic might, weight of numbers, repression and neglect of the rest.