Hibernate problem - Use of OneToMany or ManyToMany targeting an unmapped class

Question

I m finding my feet with Hibernate Annotations and I ve hit a problem I hope someone can help with   I have 2 entities  Section and ScopeTopic  The section has a List class member  so a One to Many relationship  When I run my unit test I am getting this exception      Use of  OneToMany or  ManyToMany targeting an unmapped class  com xxx domain Section scopeTopic com xxx domain ScopeTopic    I would assume that the error implies that my ScopeTopic entity isn t mapped to a table  I can t see with I have done wrong  Here are the Entity classes      Entity public class Section       private Long id      private List lt ScopeTopic gt  scopeTopics       public Section            Id     public Long getId             return id             public void setId Long id            this id   id              OneToMany      JoinTable name    section scope   joinColumns     JoinColumn name  section id                    inverseJoinColumns     JoinColumn name  scope topic id          public List lt ScopeTopic gt  getScopeTopic             return scopeTopic             public void setScopeTopic List lt ScopeTopic gt  scopeTopic            this scopeTopic   scopeTopic               Entity  Table name    scope topic   public class ScopeTopic       private Long id      private String topic       public ScopeTopic            Id     public Long getId             return id             public void setId             this id   id             public String getTopic             return topic             public void setTopic String topic            this topic   topic              I m pretty sure it s my own lack of understanding that s at fault so some guidance would be great  thanks

User · Answer

I had the same problem and I could solve it by adding the entity into persistence.xml. The problem was caused due to the fact that the entity was not added to the persistence config. Edit your persistence file:

<persistence-unit name="MY_PU" transaction-type="RESOURCE_LOCAL">
<provider>`enter code here`
     org.hibernate.jpa.HibernatePersistenceProvider
  </provider>
<class>mypackage.MyEntity</class>

...

User · Answer

Your entity may not listed in hibernate configuration file

User · Answer

Mine was not having  Entity on the many side entity   Entity    this was commented  Table name    some table   public class ChildEntity        JoinColumn name    parent   referencedColumnName    id        ManyToOne     private ParentEntity parentEntity

User · Answer

In my case a has to add my classes  when building the SessionFactory  with addAnnotationClass  Configuration configuration configure    StandardServiceRegistryBuilder builder   new StandardServiceRegistryBuilder   applySettings configuration getProperties     SessionFactory sessionFactory   configuration              addAnnotatedClass MyEntity1 class               addAnnotatedClass MyEntity2 class               buildSessionFactory builder build

User · Answer

Mostly in Hibernate   need to add the Entity class in hibernate cfg xml like-    lt hibernate-configuration gt     lt session-factory gt                 lt mapping class  xxx xxx yourEntityName   gt    lt  session-factory gt   lt  hibernate-configuration gt

User · Answer

If you are using Java configuration in a spring-data-jpa project  make sure you are scanning the package that the entity is in  For example  if the entity lived com foo myservice things then the following configuration annotation below would not pick it up    You could fix it by loosening it up to just com foo myservice  of course  keep in mind any other effects of broadening your scope to scan for entities     Configuration  EnableJpaAuditing  EnableJpaRepositories  com foo myservice repositories   public class RepositoryConfiguration

User · Answer

Your annotations look fine  Here are the things to check    make sure the annotation is javax persistence Entity  and not org hibernate annotations Entity  The former makes the entity detectable  The latter is just an addition  if you are manually listing your entities  in persistence xml  in hibernate cfg xml  or when configuring your session factory   then make sure you have also listed the ScopeTopic entity make sure you don t have multiple ScopeTopic classes in different packages  and you ve imported the wrong one

[hibernate] Hibernate problem - "Use of @OneToMany or @ManyToMany targeting an unmapped class"

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