@Entity
@Table(name="TAGS")
public class Tags implements Serializable
{

   @Id @GeneratedValue(strategy=GenerationType.AUTO)
   public long getId()
   {
      return id;
   }
   
   @ManyToMany(targetEntity=Files.class
   )
   @ForeignKey(name="USER_TAGS_FILES",inverseName="USER_FILES_TAGS")
   @JoinTable(name="USERTAGS_FILES",
         joinColumns=@JoinColumn(name="TAGS_ID"),
         inverseJoinColumns=@JoinColumn(name="FILES_ID"))
         public Set<data.Files> getUserFiles()
         {
      return userFiles;
         }
   
   @ManyToMany(mappedBy="autoTags",
         targetEntity=data.Files.class)
         public Set<data.Files> getAutoFiles()
         {
      return autoFiles;
         }
   

@Entity
@Table(name="FILES")
public class Files implements Serializable
{
   @Id @GeneratedValue(strategy=GenerationType.AUTO)
   public long getId()
   {
      return id;
   }
      @ManyToMany(mappedBy="userFiles",
         targetEntity=data.Tags.class)
   public Set<data.Tags> getUserTags()
   {
      return userTags;
   }
   @ManyToMany(targetEntity=Tags.class
         )
         @ForeignKey(name="AUTO_FILES_TAGS",inverseName="AUTO_TAGS_FILES")
   @JoinTable(name="AUTOTAGS_FILES",
         joinColumns=@JoinColumn(name="FILES_ID"),
         inverseJoinColumns=@JoinColumn(name="TAGS_ID"))
   public Set<data.Tags> getAutoTags()
   {
      return autoTags;
   }

   public void removeFile(Path path)
   {
      Session session=sessionFactory.getCurrentSession();
      
      session.beginTransaction();
      Files file=this.getFilesFromPath(path);
      if (file!=null)
      {
         for (Tags tags : file.getUserTags())   
            tags.getUserFiles().remove(file);
         session.flush();
         this.removeAutoTags(path);
         session.delete(file);
      }
      session.flush();
   }
   
   public void removeAutoTags(Path path)
   {
      Files files=this.getFilesFromPath(path);
      files.getAutoTags().clear(); // clear all autoTags
   }

SEVERE: DELETE on table 'FILES' caused a violation of foreign key constraint 'USER_FILES_TAGS' for key (3).  The statement has been rolled back.
Jun 10, 2010 9:49:52 AM org.hibernate.event.def.AbstractFlushingEventListener performExecutions
SEVERE: Could not synchronize database state with session
org.hibernate.exception.ConstraintViolationException: could not delete: [data.Files#3]
   at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:96)
   at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
   at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:2712)
   at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:2895)
   at org.hibernate.action.EntityDeleteAction.execute(EntityDeleteAction.java:97)
   at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:268)
   at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:260)
   at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:184)
   at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321)
   at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:51)
   at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1206)
   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
   at java.lang.reflect.Method.invoke(Method.java:613)
   at org.hibernate.context.ThreadLocalSessionContext$TransactionProtectionWrapper.invoke(ThreadLocalSessionContext.java:344)
   at $Proxy13.flush(Unknown Source)
   at data.HibernateORM.removeFile(HibernateORM.java:285)
   at data.DataImp.removeFile(DataImp.java:195)
   at booting.DemoBootForTestUntilTestClassesExist.main(DemoBootForTestUntilTestClassesExist.java:62)