Anacardiaceae member- INDONESIA
May be Anacardiaceae: A tree ca 8 m tall, ca 20 cm diameter. Fruits ca 15 mm diameter. ID is requested. Thank you. 
Just making a guess.. how about Mangifera caesia Jack
It seems to be matching much with your plant, provided the matuired fruits attain a bigger size. As per my observation on your plant, the fruits are very tender and yet to gain their size.
Thank you for your answer. The inflorescence is not really terminal, it is subterminal, the seeds are very hard, the carpel is very thin. I saw this tree some months ago with the same fruit size. I think this is not M. caesia. I am not sure.