Java, an island of Indonesia and the site of its capital city, Jakarta. Once the centre of powerful Hindu kingdoms, Islamic sultanates, and the core of the colonial Dutch East Indies, Java now plays a dominant role in the economic and political life of Indonesia. Java is also one of the most densely populated regions on Earth.
Java lies between Sumatra to the west and Bali to the east. Borneo lies to the north and Christmas Island to the south. It is the world's 13th largest island.
Java is almost entirely of volcanic origin; it contains no fewer than thirty-eight mountains forming an east-west spine which have at one time or another been active volcanoes. The highest volcano in Java is Mount Semeru (3,676 m). The most active volcano in Java and also in Indonesia is Mount Merapi (2,968 m).