Develop Reference

Migrating from Hibernate 3.6 to 4.2: Hibernate auto generates foreign keys

As the title suggests: I am currently migrating from Hibernate 3.6 to 4.2.
PROBLEM
After the upgrade, Hibernate started to automatically generate a foreign key that points to the same table. Now, when trying to persist a new customer, a ConstraintViolationException is thrown.
DETAILS
Here's a picture of what I mean:
Here is the code of the corresponding class:
#Entity
#Table(name = "customers")
#Inheritance(strategy = InheritanceType.JOINED)
public abstract class Customer extends AbstractModel {
public Customer(final Provider provider) {
this.provider = provider;
}
#Required
#ManyToOne(cascade = CascadeType.REFRESH)
public Provider provider;
#MaxSize(1023)
public String note;
public String getNote() { return note; }
...
}
As you can see, it extends from AbstractModel which is a #MappedSuperclass and contains the id property which serves as a primary key for all of our model classes. It's a #GeneratedValue.
It's a superclass itself. I don't know whether it's important so I am just going to include the code and schema of one of its child classes:
And the corresponding code:
#Entity
#Table(name="unregistered_customers")
public class UnregisteredCustomer extends Customer {
#MaxSize(MAX_SIZE_OF_NAMES_AND_IDENTIFIERS)
#Column(nullable = false, length = MAX_SIZE_OF_NAMES_AND_IDENTIFIERS)
public String userName;
#Email
#MaxSize(MAX_SIZE_OF_EMAIL_ADDRESSES)
#Column(unique = false, length = MAX_SIZE_OF_EMAIL_ADDRESSES)
public String email;
#MaxSize(MAX_SIZE_OF_NAMES_AND_IDENTIFIERS)
#Column(length = MAX_SIZE_OF_NAMES_AND_IDENTIFIERS)
public String mobile;
public UnregisteredCustomer(final Provider provider) {
super(provider);
}
RESEARCH
I already looked into the migration guide but nothing in there seems to be related to my issue.
I also looked into the Hibernate documentation especially into the section dealing with #Inheritance. Sadly, I didn't find anything concerning auto generated foreign keys.
QUESTION
How do I stop Hibernate from adding this self-referencing foreign key?
EDIT 1
As requested, the super class:
#MappedSuperclass
public abstract class AbstractModel extends AbstractBaseModel {
#Id
#GeneratedValue
public Long id;
public Long getId() {
return id;
}
#Override
public Object _key() {
return id;
}
}
Also, the super class of the super class:
#MappedSuperclass
public abstract class AbstractBaseModel extends GenericModel {
public static final int MAX_SIZE_OF_NAMES_AND_IDENTIFIERS = 80;
public static final int MAX_SIZE_OF_COMMENTS_AND_DESCRIPTIONS = 5000;
public static final int MAX_LIST_SIZE = 30;
public static final int MAX_SIZE_OF_EMAIL_ADDRESSES = 255;
public static final int MAX_SIZE_OF_JSON_CONTENT_FIELDS = 65535;
#Column(nullable = false, unique = true)
public String uuid;
#Column(nullable = false)
public Long created;
public DateTime getCreatedAsDate() {
return DateUtil.dateTimeWithSystemTimezone(created);
}
#Column(nullable = false)
public Long lastModified;
#PrePersist
protected void prePersist() {
final Long nowInMillis = DateUtil.dateTimeWithSystemTimezone().getMillis();
if (uuid == null) {
uuid = UuidUtil.newUUIDAsString();
Logger.trace("Created new Uuid for entity: %s", uuid);
}
if (created == null) {
created = nowInMillis;
}
if (lastModified == null) {
lastModified = nowInMillis;
}
}
#PreUpdate
protected void preUpdate() {
lastModified = DateUtil.dateTimeWithSystemTimezone().getMillis();
}
#Override
public boolean equals(final Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
final AbstractBaseModel other = (AbstractBaseModel) obj;
return new EqualsBuilder().append(uuid, other.uuid).isEquals();
}
#Override
public int hashCode() {
return new HashCodeBuilder().append(uuid).toHashCode();
}
}

Put #Inheritance(strategy = InheritanceType.JOINED) to the parent entity (AbstractModel) not to the child. And customize the foreign key constraint using #PrimaryKeyJoinColumn at your child entity. Check out Part 4 (Joined Table) at https://www.baeldung.com/hibernate-inheritance to see it more clearly!

Hibernate with mysql overwrites pk

Well, I'm using Hibernate for the first time and, unexpectedly, it works. Except for one thing: an insert with a pk already inserted overwrite the record instaed of preventing it.
That's my simple code:
#Controller
public class SimpleController {
#Autowired
UserRepository userRepository;
#GetMapping("/mainPage")
public String viewMainPage(){
return "mainPage";
}
#GetMapping("/nuovo-utente")
public String viewInserisciUtente(Model model){
model.addAttribute("nuovoUtente", new Utente());
return "nuovo-utente";
}
#PostMapping("/nuovo-utente")
public String memorizzaUtente(#ModelAttribute Utente utente){
userRepository.save(utente);
return "output";
}
}
#Entity
public class Utente {
#Id
private int id;
private String citta=null;
private String genere=null;
private String data_nascita=null;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getCitta() {
return citta;
}
public void setCitta(String citta) {
this.citta = citta;
}
public String getGenere() {
return genere;
}
public void setGenere(String genere) {
this.genere = genere;
}
public String getData_nascita() {
return data_nascita;
}
public void setData_nascita(String data_nascita) {
this.data_nascita = data_nascita;
}
}
Any help will be appreciated.
EDIT: I've added the entity class to help you understanding my problem. Hoping that this will help.
Thanks you all

If you look at CrudRepository documentation, then we don't have update method, but we only have save method, which is used to add or update existing records.
In your case, you might have updated an entity (except its Id field) and tried saving the entity. So, CrudRepository will update the existing value for given Id, since it is already present.

Try adding ID generation strategy to id field.
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;

Extending/modifying generated entities in Hibernate

I am creating a REST api service for a mysql database. I've generated classes using IntelliJ's persistence tool. It does a pretty good job.
There are some quirks to the schema that I am working with. The users want the endpoints to be accessible by another property other than the "id" primary key column.
Ex: /object/<name property>' versus/object/`.
Here is the catch though. The schema can change. The name property is not going anywhere though so I can safely assume that will always be on the object.
I've learned that you can use Superclasses to force these generated entites to have custom properties without affecting the database schema. I dont want to make a model change in the generated entity and have that update the database table layout as it is not my database.
I have a class called Animal.
#Entity
#Table(name = "animals", schema = "xyz123", catalog = "")
public class AnimalEntity extends AnimalSuperclass {
private Integer id;
private String name;
private String description;
#Id
#Column(name = "id", nullable = false)
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
#Basic
#Column(name = "name", nullable = true, length = 80)
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
#Basic
#Column(name = "description", nullable = true, length = 255)
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
#Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
RoleEntity that = (RoleEntity) o;
return Objects.equals(id, that.id) &&
Objects.equals(name, that.name) &&
Objects.equals(description, that.description);
}
#Override
public int hashCode() {
return Objects.hash(id, name, description);
}
}
I have to manually add extends AnimalSuperclass. Which is fine for now. Eventually I am going to try to generate these using .xmls on runtime.
Then I have this superclass..
#MappedSuperclass
public class AnimalSuperclass implements Serializable {
private String testMessage;
private String name;
private Integer id;
#Transient
public String getTestMessage() {
return this.testMessage;
}
public void setTestMessage(String id) {
this.testMessage = testMessage;
}
}
What I want to do is force the #Id annotation to be on the name property from within the superclass. Something like this..
#MappedSuperclass
public class AnimalSuperclass implements Serializable {
private String testMessage;
private String name;
private Integer id;
#Transient
public String getTestMessage() {
return this.testMessage;
}
public void setTestMessage(String id) {
this.testMessage = testMessage;
}
#Basic
#Id
#Column(name = "name", nullable = false, length = 15)
private String getName() {
return name;
}
private void setName(String name) {
this.name = name;
}
#NaturalId
#Column(name = "id", nullable = false)
private Integer getId() {
return id;
}
private void setId(Integer id) {
this.id = id;
}
}
How do I go about doing that? Currently this throws an error when I hit the endpoint: {"cause":null,"message":"Id must be assignable to Serializable!: null"}
Java is not my first language so I am not an expert by any means. But from what I've read, its not possible to override subclass properties from the superclass. Is there a better way to approach this, maybe by using RepositoryRestConfiguration? I am using PagingAndSortingRepository to serve these entities. I cannot extend the entities and use my superclass as a child as that creates a dType property in the schema and I cannot alter the table layout.

There is no hard link between the request and your entity. In your repository you can write methods that can query the data that is brought it from the request.
For example if they are requesting a name you can do something like
Page<AnimalEntity> findByName(String name, Pageable pageable);
in your Repository. Spring will take care of the rest and then you can call this in your controller.
#Service
public class AnimalService {
#Autowired
private AnimalEntityRepository animalRepo;
public Page<AnimalEntity> findAnimal(String name) {
Page<AnimalEntity> animals = animalRepo.findByName(name, new PageRequest(1,20));
return animals;
}
}
One thing to mention is that depending on how you configured Hibernate when sending an entity back to the client and the entity is seralized you might get an failed to lazy initialize error. If that is the case your entities will have to be converted to a POJO (plain old java object) and that sent back.

Remote EJB and JPA #Version

A multi-tiered application that I am developing accesses its database through a Payara application server. Originally I was using webservices (jax-ws) to provide the access. That decision was prompted by the ease of creating the services by using the #WebService and #Stateless annotations on my entity facade classes.
Due to some limitations of webservices (things like equals and hashCode methods not being created in the webservice interface), I decided to try to use EJB's to accomplish the same functionality. Using the webservices I was able to successfully perform all CRUD functionality on all of the database entities. All of my entity classes extend an AbstractEntity class, which is annotated #MappedSuperClass.
#MappedSuperclass
public abstract class AbstractEntity {
#Column(name = "UUID")
#Basic
private String uuid;
#Version
#Access(AccessType.FIELD)
#Column(name = "Revision")
#Basic
private long revision;
public AbstractEntity() {
uuid = UUID.randomUUID().toString();
}
public String getUuid() {
return uuid;
}
public void setUuid(String uuid) {
this.uuid = uuid;
}
/**
* #return entity's database primary key if persisted
*/
public abstract Long getId();
public long getRevision() {
return revision;
}
public void setRevision(long revision) {
this.revision = revision;
}
/**
* #return true if this entity is persisted to database, false
otherwise.
*/
public boolean isPersisted() {
return getId() != null;
}
#Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj instanceof AbstractEntity) {
return this.uuid.equals(((AbstractEntity) obj).uuid);
}
return false;
}
#Override
public int hashCode() {
return uuid.hashCode();
}
}
The client application correctly looks up the remote interfaces through JNDI, and I'm able to run my methods to query the data and return result lists exactly the same as I can using webservices. The problem, however, is in the version number and uuid that are returned with each entity instance. In all cases, the revision number that is returned is 0, and the revision and uuid don't match the revision and uuid stored in the database. I have verified that the result of my query on the server contains entities that have the correct version numbers, but when the entities get to the client, all of them are set to 0. Of course, if I make any changes to the entity on the client and then try to update the entity, I get an optimistic locking exception on the update method.
Does this have something to do with the entities being detached from the database? The update method is:
#Override
public ShiplistItem updateShipList(ShiplistItem shipitem) {
LOGGER.log(Level.INFO, "Entering updateShipList.");
LOGGER.log(Level.INFO, "shipitem: {0}", shipitem.toString());
if (shipitem.isPersisted()) {
return em.merge(shipitem);
} else {
em.persist(shipitem);
return shipitem;
}
}
I don't understand why the webservice would return the entities correctly, but the ejb seems to neglect the stored values for revision and uuid.
All help is appreciated!!
EDIT - Entity class snippet
public class ShiplistItem extends AbstractEntity implements
Serializable, Comparable<ShiplistItem> {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(unique = true, nullable = false)
private Long id;
....
EDIT #2
#Override
public List<ShiplistItem> listShipListByDate(String date) {
Query query = em.createQuery("SELECT s from ShiplistItem s
where s.shipdate = :shipdate", ShiplistItem.class)
.setParameter("shipdate", date);
LOGGER.log(Level.INFO, "SQL: {0}.", query.toString());
List<ShiplistItem> result = new ArrayList<>();
try {
result = (List<ShiplistItem>) query.getResultList();
} catch (Exception ex) {
LOGGER.log(Level.INFO, "No shipping list for date {0}", date);
}
for (ShiplistItem shiplistItem : result) {
LOGGER.log(Level.INFO, "revision: {0}",shiplistItem.getRevision());
}
LOGGER.log(Level.INFO, "shiplist size: {0}", result.size());
return result;
}

JPA 2.1 Attribute Converter convert enum still insert int

i'm using spring data jpa with hibernate as provider.
i'm trying to persist my enums on varchar(enum.tostring) instead of (0,1,2)
my enum class:
public enum MagasinType {
PRINCIPAL {
#Override
public String toString() {
return "Principale".toUpperCase();
}
},
SECONDARY {
#Override
public String toString() {
return "Secondaire".toUpperCase();
}
},
MOBILE {
#Override
public String toString() {
return "Mobile".toUpperCase();
}
};
public abstract String toString();
}
my converter
#Converter(autoApply = true)
public class MagasinConverter implements attributeConverter <MagasinType,String>{
#Override
public String convertToDatabaseColumn(MagasinType magasinType) {
switch (magasinType){
case MOBILE:return "MOBILE";
case PRINCIPAL:return "PRINCIPAL";
case SECONDARY:return "SECONDARY";
default:throw new IllegalArgumentException("valeur incorrecte" + magasinType);
}
}
#Override
public MagasinType convertToEntityAttribute(String s) {
switch (s){
case "MOBILE": return MagasinType.MOBILE;
case "SECONDARY": return MagasinType.SECONDARY;
case "PRINCIPAL": return MagasinType.PRINCIPAL;
default:throw new IllegalArgumentException("valeur incorrecte" + s);
}}}
my entity
#Entity
#Table(name = "MAGASIN")
public class Magasin extends AbstractEntity {
#Column(name = "LIBELLE", nullable = false)
private String libelle;
#Column(name = "DESCR")
private String descr;
#Convert(converter = MagasinConverter.class)
private MagasinType type;
#Column(name = "LOCATION")
private String localisation;
#Version
private long version;
//getters setters omitted
}
my java config : https://gist.github.com/anonymous/480ef7a58cdcc50e7481
my app.properties : https://gist.github.com/anonymous/685eaca98fcba9c33872
and finally my test method : https://gist.github.com/anonymous/8bb60fee39a201558e19
please help me on it, i want to use #convert new jpa2.1 feature instead of
#enumerated

i tried to put the annotation on the getter and it works.
now i can call the #convert to convert enums to strings and visversa when pulling from database.
the same problem happened when i added #manytoOne on my class attribute, i got a weired problem, no column was added to the table entity.
but when i annotated the getter. every thing was ok.
please take a look at my github repo to further infos
https://github.com/zirconias/RFID_REWRITE