In Dutch, it was called Nederlandsch-Indië. In English it was Dutch East Indies to separate it from the Dutch West Indies. It remained under the flag of the Netherlands until March 8, 1942 when the Royal Dutch East Indies Army surrendered in Java to the Japanese. After Japan's 1945 surrender, nationalist leaders declared independence, while the Dutch attempted to reassert their control. The Netherlands recognized Indonesian independence in December, 1949, except for "Netherlands New Guinea/Western New Guinea"(Nederlands-Nieuw-Guinea) which was not ceded to Indonesia until 1963. Summarized from Wikipedia. So I guess the answer to your question is Java, Nederlandsch-Indië until March 8, 1942.