Janaka refers to a historical title held by the monarchs of Videha, an ancient kingdom in India. According to the Hindu epic Ramayana, these rulers governed from the capital city of Mithila. The title was first adopted by King Mithi, who was the son of King Nimi.
In the context of the itihasa literature, Janaka is specifically identified as the ruler married to Sunayana and the father of Sita and Urmila. While the user prompt mentions a city in Indonesia, the provided source material identifies Janaka exclusively as a royal title and a figure within Hindu mythology.