ClassCastException when changing a collection association to a set if @PreUpdate listener exists in Hibernate

Issue

• An association is defined between two entities and a PreUpdate listener is used

  public class EmployeeListener {
      @PreUpdate
      void onPreUpdate(Object o) {
      }
  }
  
  @Entity
  @EntityListeners( EmployeeListener.class )
  public class Employee {
      ...
      @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
      protected Collection<Task> tasks;
      ...
  }
  
  @Entity
  public class Task {
      ...
  }
  

• Though the association is defined to use collection/bag semantics, it is being assigned a set

  HashSet<Task> tasks = new HashSet<Task>();
  tasks.add(new Task("Some work"));
  employee.setTasks(tasks);
  entityManager.merge(employee);
  entityManager.flush();
  

• A ClassCastException is raised during flush after the update of the association

  java.lang.ClassCastException: java.util.HashSet cannot be cast to org.hibernate.collection.spi.PersistentCollection
      at org.hibernate.event.internal.FlushVisitor.processCollection(FlushVisitor.java:43)
      at org.hibernate.event.internal.AbstractVisitor.processValue(AbstractVisitor.java:104)
      at org.hibernate.event.internal.AbstractVisitor.processValue(AbstractVisitor.java:65)
      at org.hibernate.event.internal.AbstractVisitor.processEntityPropertyValues(AbstractVisitor.java:59)
      at org.hibernate.event.internal.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:166)
      at org.hibernate.event.internal.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:235)
      at org.hibernate.event.internal.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:94)
      at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:38)
      at org.hibernate.internal.SessionImpl.doFlush(SessionImpl.java:1483)
      at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1469)