Assuming that:
Entity A references a collection of Entity B.
Entity B does not reference Entity A.
Unidirectional relationship has only an owning side, which is this case must be Entity A.
Entity A is mapped to a table named A.
Entity B is mapped to a table named B.
There is a join table that is named A_B (owner name first).
The JPA relationship referred here is : Unidirectional Many to Many Relationships.
I think unidirectional one to many is also possible even though there is no option for this.
