MERCENARY SOLDIERS IN JAVA'S HISTORY
If you pay attention to Javanese history, you will find that Javanese people used to maintain mercenaries. The mercenaries recruited were usually from Indonesian tribes known for their fighting skills, such as Madurese, Balinese, Bugis and Makassar.
In the past, Majapahit maintained many mercenaries from Madura, Demak too. In the Arya Panggiri (Pajang) era they were recorded as maintaining mercenaries from Bali. So then in the Islamic Mataram era they maintained mercenaries from Madura, Bugis and Makassar.
Usually the Javanese Commanders and Heroes relax at the back when fighting, the mercenaries go first, then if the mercenaries feel unable to do so, the Javanese Heroes intervene.
The Javanese ruler's method of recruiting mercenaries seems to have been imitated by the Dutch VOC at a later date. Where they recruited mercenaries from Java as commanders, mercenaries from other tribes who also came from Madura, Bugis, Makasar and Bali. During the VOC era, they recruited more varied mercenaries, because they included mercenaries from Ambon, Nusa Tenggara, Manado and other tribes.