@ElementCollection Map of @Embeddable gets not persisted when field values are equal

Question

I have a problem with inserting elements into an @ElementCollection represented by a Map. When inserting elements with same values, they are not persisted. Given following @Entity and its @Embeddable:

@Entity
@Table(name = "category", catalog = "my_db", schema = "")
public class Category implements Serializable {

  @Id
  @Column(name = "id")
  private Integer id;

  @ElementCollection(fetch = FetchType.LAZY, targetClass = CategoryLabels.class)
  @CollectionTable(name = "category_labels", joinColumns =
  @JoinColumn(name = "category_id"), catalog = "my_db")
  @MapKeyColumn(name = "language_id")
  private Map<Integer, CategoryLabels> labels = new HashMap<Integer, CategoryLabels>();

...
}


@Embeddable
public class CategoryLabels implements Serializable {
  @Column(name = "label1")
  private String label1;

  @Column(name = "label2")
  private String label2;

...
}

Database entries

+-------------+-------------+-----------+---------+
| category_id | language_id | label1    | label2  |
+-------------+-------------+-----------+---------+
|         183 |           1 | Capacity  | Timings |
|         183 |           2 |           |         |
+-------------+-------------+-----------+---------+

Inserting works fine, if label1 and label2 differ for each map entry (as seen above).

But if I add one entry that has the same values for label1 and label2 as another entry, the second one is never persisted to the database. For example, if I add an entry to the Map with both labels empty (like the second entry in the example) but with language_id=3, this will never get persisted.

I am aware of this common problem: http://en.wikibooks.org/wiki/Java_Persistence/ElementCollection#Common_Problems and that embedded objects without ID are checked for their fields and foreign key @JoinColumns as ID. This does not seem to work in my case, the foreign key in the @JoinColumn is completely ignored for the ID-check.

Is this a bug in Eclipselink or am I doing something wrong?

EDIT:

I've set -Declipselink.logging.level=FINEST and this reveals that no SQLs are executed for the second and following entries with empty labels.

Additionally I've made a sample project with which you can reproduce the problem: http://bit.ly/1bR8ywO

Answer 1

Just tested again and I found out, that the problem is dedicated to the transaction management. I didn't want to use transactions at all so I annotated my SLSB with @TransactionManagement(TransactionManagementType.BEAN). When I remove this, the transaction gets managed by the container and then the update works as expected.

Setting the transaction management to container managed is not the solution I hoped for but this works for now. Still I think this is a bug in eclipselink.