What is Java famous for?

Hint:
56.7% of the population of Indonesia is found in Java and is the most populated island in the world.
Four of the eight UNESCO World Heritage sites in Indonesia are situated in Java.
Many ancient kingdoms relied on Java for rice.

Complete answer:
Java is an island of Indonesia, bordered by the Indian Ocean to the south and the Java Sea to the north. It was the base of the mighty Hindu-Buddhist empires, the Islamic sultanates, and the centre of the colonial East Indies of the Netherlands. Java was also the focus of Indonesia's fight for independence in the 1930s and 1940s. Java is politically, economically and culturally dominant in Indonesia. Four of the eight UNESCO World Heritage sites in Indonesia are located in Java: Ujung Kulon National Park, Borobudur Temple, Prambanan Temple and Sangiran Early Man Site.

Java has been famous for rice surpluses and rice exports since ancient times, and rice farming has contributed to the island's population growth. Indonesia is the third largest producer of rice in the world and also one of the largest consumers of rice in the world. The country's rice area rose from 11,4 million hectares in 1995 to 13,2 million hectares in 2010, accounting for 24 per cent of the total agricultural area. Rice is the largest food crop in this country.

The Government of Indonesia has had two major initiatives to increase rice production:
Rice transmigration scheme 2009: revival of the Suharto-era transmigration scheme in which large numbers of farmers from Java will be given land on the outer islands to grow rice.
Merauke Integrated Food and Energy Estate (MIFEE) 2009: where the Government is targeting a remote part of Papua Province (Merauke Regency) for major commercial agricultural activities, including rice, maize, sorghum, sugar cane, palm oil, timber, livestock, poultry and fish.

Rice production is highly concentrated on the islands of Java and Sumatra; almost 60% of total production comes from Java alone.

Note:
Java has been Indonesia's most established island since the time of East Indies in the Netherlands and continues to be so today in the modern Republic of Indonesia.
Based on the 2012 statistical data published by Statistics Indonesia, Java alone contributes at least 57.51 per cent of Indonesia's GDP.
Indonesian nationalism first took place in Java in the early 20th century, and the fight to secure the country's independence after World War II was based on Java.