I saw something similar with an older, but still very small jujube that I have. The fruits ended up the size of very small olives. I ate some dried, and they were definitely not as tasty as those on the full size jujube trees that I have. I am confident that when this little one grows big enough, it will bear higher quality fruit though...

So how big is your tree? Is there any chance that it is a seedling instead of a named cultivar? Could it also possibly be that you are seeing the rootstock and the grafted scion broke off or something? All of these scenarios could give you undersized, unappetizing fruit.

Of course there is also the possibility of poor growing conditions, not enough water and soil fertility, etc., but I'm assuming you have this under control, especially since jujubes are really forgiving anyway.

If it is a tree size thing, just wait a few years. If it is due to the genetics of the tree (a seedling or rootstock only tree) you probably will want to get rid of it and start again, or maybe even consider trying to graft onto it.

Hope this helps...

Thank you umfruit, my tree is about 6 feet tall, I bought it from a good nursery. I remember it beared some ( about 30 ) full size jujubes (but no premature ones like this year) in the year before last year. I agree what you said it may be too young. Thank you for your prompt help.