The @javax.persistence.ManyToOne annotation defines a single-valued association to another entity class that has many-to-one multiplicity. In Naked Objects' terms this is a property whose return type is another entity. In database terms, this is like a foreign key. The @ManyToOne annotation goes in the "child" entity, specifically on the property that points to the "parent" entity.

It is not normally necessary to specify the target parent entity explicitly since it can usually be inferred from the type of the object being referenced.

The @ManyToOne sometimes combines with the @OneToMany annotation in the parent entity, making the association bidirectional. See Section 4.5, “One-to-Many” for more details.