Java (Indonesian: Jawa) is an island of Indonesia. With a population of 135 million (excluding the 3.6 million on the island of Madura which is administered as part of the provinces of Java); Java is the world's most populous island; and one of the most densely populated places in the world. Java is the home of 60 percent of the Indonesian population. The Indonesian capital city; Jakarta; is located on western Java.

Much of Indonesian history took place on Java. It was the center of powerful Hindu-Buddhist empires; the Islamic sultanates; and the core of the colonial Dutch East Indies. Java was also the center of the Indonesian struggle for independence during the 1930s and 40s. Java dominates Indonesia politically; economically and culturally.

Formed mostly as the result of volcanic eruptions; Java is the 13th largest island in the world and the fifth largest island in Indonesia. A chain of volcanic mountains forms an east-west spine along the island. It has three main languages; though Javanese is dominant; and it is the native language of about 60 million people in Indonesia; most of whom live on Java. Most of its residents are bilingual; with Indonesian as their first or second languages. While the majority of the people of Java are Muslim; Java has a diverse mixture of religious beliefs; ethnicities; and cultures.

Java is divided into four provinces; West Java; Central Java; East Java; and Banten; and also two special regions; Jakarta and Yogyakarta.