Handle 404 error while adding a pet to an owner

[arey]

The POST /owners/{ownerId}/pets does not return a 404 error when the ownerId does not exist but an error 400

{ 
   "className": "org.springframework.dao.DataIntegrityViolationException", 
   "exMessage": "could not execute statement [integrity constraint violation: foreign key no parent ; FK_PETS_OWNERS table: PETS value: 222] [insert into pets (birth_date,name,owner_id,type_id,id) values (?,?,?,?,default)]; SQL [insert into pets (birth_date,name,owner_id,type_id,id) values (?,?,?,?,default)]; constraint [FK_PETS_OWNERS]"
}

Same behaviour when a Pet does not exist