One of the dynamic forces of interregional shipping and trade was the interdependence of supply and demand between regions in the Indonesian archipelago. This created a kind of symbiosis relationship. Since the pre-colonial era, Java supplied rice to the Outer Islands such as the Maluku Islands and even Malacca. The Outer Islands produced cash crops, such as spices and many kinds of forest products (camphor, kemenyan,19 gambier,20 sandalwood, etc.). People in Java did not consume these commodities on a large scale but these goods were re-exported to Western countries. A kind of barter took place, in which local people obtained textiles, metal goods, jewellery, etc. in exchange for spices. Thus, before the arrival of Portuguese in the 16th century there were no trading commodities sent directly from the Maluku islands to Western Europe. Java’s essential position is shown here, not only as a supplier of commodities to other regions but also as the main entrepot of trade between the Maluku Islands and Malacca. Java acted as a warehouse of imported commodities before they were distributed to the surrounding regions of the Outer Islands such as Palembang, Lampung, Banjarmasin, Bali and Lombok, and the Maluku islands. Ports along the northern coast of Java became a rendezvous for traders of the Outer Islands
as well as their foreign fellows. Shortly, there had been a certain degree of specialization in supply and demand in trading system among regions in the Indonesia archipelago.