What peoples inhabited the Byzantine Empire under Justinian?

During the reign of Justian, the Byzantine Empire was mostly inhabited by Greeks, as well as Slavs, Syrians, Armenians, Arabs and Jews. Given the predominantly Greek population, the state language was soon replaced by Greek.
Such a number of nationalities of the empire required a large amount of resources from the government, which the emperor did not reckon with. Such an act led to the outrage of the Byzantine people, therefore, it was during the reign of Emperor Justian that the country underwent the most powerful uprisings in the entire history of the empire.