(JPA) Correct way to remove entity ?

[David Balažic]

Hi!

In a project a bug appeared after some "unrelated" changes and we had to add a line of code to fix it.

Old code:

  
public void removeFoo(long fooId) { // is an EJB method
    	Foo f = entityManager.find(Foo.class, fooId);
    	entityManager.remove(f);
}

New code:

   
public void removeFoo(long fooId) { // is an EJB method
    	Foo f = entityManager.find(Foo.class, fooId);
    	f.getBar().getFoos().remove(f); // new line added to fix problem
    	entityManager.remove(f);
}

Mappings:

@Entity
@Table( name = "TBL_FOO" )
public class Foo implements Serializable
{

	@ManyToOne( fetch = FetchType.EAGER )
	@JoinColumn( name = "BAR_ID", nullable = false, insertable = true, updatable = true )
	private Bar bar;
// rest snipped
}

// in other file:


@Entity
@Table( name = "TBL_BAR" )
public class Bar implements Serializable
{
	@OneToMany( fetch = FetchType.EAGER, cascade = CascadeType.ALL, mappedBy = "bar" )
	private Set<Foo> foos = new HashSet<Foo>();
// rest snipped
}

The change that I suspect triggered the problem is that change from FetchType.LAZY to FetchType.EAGER in Bar.java.
We got this exception after removeFoo() returns:

javax.persistence.EntityNotFoundException: deleted entity passed to persist: [com.acme.Foo#<null>]
        at org.hibernate.ejb.AbstractEntityManagerImpl.throwPersistenceException(AbstractEntityManagerImpl.java:613)
        at org.hibernate.ejb.AbstractEntityManagerImpl$1.beforeCompletion(AbstractEntityManagerImpl.java:524)
        at com.arjuna.ats.internal.jta.resources.arjunacore.SynchronizationImple.beforeCompletion(SynchronizationImple.java:114)
(rest in com.arjuna.. and org.jboss... not very informative)

This is run under JBoss 4.2.3.GA on Windows XP Pro SP3 with Sun Java 1.6.0u20


So the question is:
Is this the correct way to remove entities? That is manually removing references to it from other entities?
Sound like a lot of "unneeded" work.

Regards,
David