It is a tree that is of two varieties here.
There is the Javilla that is native and the more popular Javilla extrangera
The native variety is a very thorny bark and there is an expression: Puerco no se rasca en javilla
Which means that even pigs don't use the javilla to scratch their backs.
The javilla extrangera is a broad-leaf tree that has green tennis-ball sized, totally useless fruits, which are good for nothing
I know of, except for throwing at things like stray dogs. It is ued as a shade tree by many people.
There, now you know the rest of the story.
HB