If they are real Blue Java/ice cream, you picked them too early. They don't ripen of tree in my experience. They will just rot. Mine I had to leave on the tree until yellow and well ripened because when I picked a hand and tried ripening off tree they just didn't ripen and went bad/rotted.
Did they ripen for you? if so I doubt they are real.
From the color I'd doubt it too. Too green and not enough of the silver/blue dusted look.
I'd guess, namwah.
Helps to see the plants, in bloom with the flower and fruit hanging.
Here are some of my real Blue Java plants:
These didn't ripen at all off tree:
