This a fruit called Rambootan, usally found in tropicall climate areas. It tastes sweet and little sour. I have a dozen of Rambootan trees cultivated in my farm area . but only one gave the fruit ,others had flowers .Whats the reason is that there is Males & females for this tree. Males will only flower ,females will flower and bear fruit. The fruit can be harvested when it has become reddish color.