JoinColumn[] joinColumns default {}

(Optional) The foreign key columns of the collection table which reference the primary table of the entity. The default only applies if a single join column is used. The default is the same as for JoinColumn (i.e., the concatenation of the following: the name of the entity; "_"; the name of the referenced primary key column.) However, if there is more than one join column, a JoinColumn annotation must be specified for each join column using the JoinColumns annotation. In this case, both the name and referencedColumnName elements must be specified by each such JoinColumn annotation.