spring - how to add @onetoone mapping for self entity in hibernate -

how add one-to-one mapping self entity. in example. want have parent-child relationship person itself.

@entity @table(name="person") public class person {  @id @column(name="personid") private int id;  @onetoone @joincolumn() private person parentperson; } 

here example of bidirectional self mapping @onetoone (i change column names sql notation):

@entity @table(name="person") public class person {      @id     @column(name="person_id")     private int id;      @onetoone     @joincolumn(name = "parent_person_id")     private person parentperson;      @onetoone(mappedby = "parentperson")     private person childperson; } 

but, don't understand why want use @onetoone in case.