Eugenia reinwardtiana, fruit can be variable from plant to plant, as well as on the same plant, and due to growing conditions.
They can be found just off the beach in full sun. Seem to be pretty tough.
Fruit there seem a little less fleshy. Sometimes plants in the shade have more fleshy fruit.
I usually collected seed from nice fruiting plants, and didn't bother with seed from thin fleshed fruit on rocky coastlines or in the dunes.
Thinking there might be tougher beach types and also forest types ?