In January 1942, Japan invaded the Netherlands East Indies. The Dutch surrendered two months later in Java, with Indonesians initially welcoming the Japanese as liberators. The subsequent Japanese occupation of Indonesia during the remainder of World War II saw the fundamental dismantling of the Dutch colonial state's economic, political and social structures, replacing it with a Japanese regime. In the decades before the war, the Dutch had been overwhelmingly successful in suppressing the small nationalist movement in Indonesia such that the Japanese occupation proved fundamental for Indonesian independence. However, the Indonesian Communist Party founded by Dutch socialist Henk Sneevliet in 1914, popular also with Dutch workers and sailors at the time, was in strategic alliance with Sarekat Islam (q.v.) as early as 1917 until the Proclamation of Indonesian Independence and was particularly important in the fight against Japanese occupation of the Dutch East Indies in the Second World War. The Japanese encouraged and backed Indonesian nationalism in which new indigenous institutions were created and nationalist leaders such as Sukarno were promoted. The internment of all Dutch citizens meant that Indonesians filled many leadership and administrative positions, although the top positions were still held by the Japanese.