Looks exactly like the fruit in the link that BMc provided! Turns yellowish when ripe. Propagate by seed, cuttings, air-layering? Old tree, tall and storm damaged. Mixed in with the tamarinds, java plums, carambola and martin sapodilla. Thanks for the ID on this tree. Would like to salvage this one, very interesting to see how the fruit just grows out of the trunk on pedicles.