Following World War II and the end of the Dutch Empire, the Republic of Indonesia underwent a social revolution known as the Indonesian National Movement, commonly referred to as the Indonesian War of Independence. The Netherlands turned up the authority of the Dutch East Indies to the Republic of the United States of Indonesia between the time of Indonesia's independence declaration in 1945 and the end of 1949.
Throughout the four-year conflict, there were two significant international diplomatic interventions, as well as intermittent but violent armed conflict, as well as political and social unrest within Indonesia. Dutch military forces (and, for a while, the forces of the World War II allies) were able to maintain control over the major cities, industrial facilities, and Republican strongholds on Java and Sumatra, but they were unable to maintain authority over the surrounding countryside. By 1949, the Netherlands had given up control of the Dutch East Indies to the Republic of the United States of Indonesia due to pressure from other countries, the threat by the United States to stop all economic aid for the Netherlands' post-World War II reconstruction efforts, and a partial military standoff.
Except for New Guinea, the revolution signaled the end of colonial rule in the Dutch East Indies. Additionally, it substantially altered ethnic castes and diminished the authority of many local kings (raja). The majority of the population's economic or political circumstances did not dramatically change, even though some Indonesians were able to attain a more significant position in the business.
The "Day of National Awakening," observed on May 14, 1908, marks the beginning of the Indonesian independence movement (Indonesian: Hari Kebangkitan Nasional). In the first half of the 20th century, movements in support of Indonesian nationalism and independence from Dutch colonialism—including Budi Utomo, the Indonesian National Party (PNI), Sarekat Islam, and the Indonesian Communist Party (PKI)—grew quickly. To gain Indonesian self-rule, Budi Utomo, Sarekat Islam, and others joined the Volksraad ("People's Council"), which was founded by the Dutch. [20] Others opted for a confrontational approach in which they pressed the Dutch East Indies colony for the right to self-government. The most notable of these leaders were Sukarno and Mohammad Hatta, two students and nationalist leaders who had benefited from the educational reforms of the Dutch Ethical Policy.
During World War II, Japan held Indonesia for 3 and a half years, which had a significant role in the uprising that followed. The Dutch East Indies were quickly conquered by the Japanese after only three months of initial attacks because the Netherlands had no power to repel the Japanese troops. The Japanese promoted nationalism on Java and to a lesser extent on Sumatra, Indonesia's two largest islands. Although this was done more for Japanese political gain than out of a sincere desire to help Indonesian independence, it nonetheless elevated political figures like Sukarno and led to the creation of new Indonesian institutions (like neighborhood organizations). The Dutch-built commercial, administrative, and political infrastructure were largely dismantled and replaced by the Japanese, which had an equally important impact on the later revolution. On 7 September 1944, with the war going badly for the Japanese, Prime Minister Koiso promised independence for Indonesia, but no date was set. For supporters of Sukarno, this announcement was seen as a vindication of his collaboration with the Japanese.