This apple, has no link to roses or apples. It is in the guava family of fruits and the other name is Syzgium jambos. It is a small shrub tree in south Asia. It’s also spread in other world areas and was used like ornament at first. It is invasive and grows really quick, it even overcrowds other flowers or plants.
It is much like the guava even identical. But, it has a different smell, texture and flavor too.