error trying to bind ManyToMany relationShip

Question

I am using ebean with Play Framework 2.4

I cant understand where is the problem. Here are a simplified version of my two beans:

@Entity
public class ArtifactEntry extends Model {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    public int id;

    @play.data.validation.Constraints.Required
    public String name;

    @ManyToMany(mappedBy = "artifacts")
    public List<TimestampEntry> timestamps = new ArrayList<TimestampEntry>();
}

And my other bean:

@Entity
public class TimestampEntry extends Model {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    public int id;

    @play.data.validation.Constraints.Required
    @Index
    public String timestamp;

    public Date timestampDate;

    @play.data.validation.Constraints.Required
    @Index
    public String buildNumber;

    @ManyToMany(cascade = CascadeType.ALL)
    public ArtifactsList artifacts = new ArtifactsList();

    public static class ArtifactsList extends ArrayList<ArtifactEntry> {

    }
}

The error message is:

1) Error injecting constructor, javax.persistence.PersistenceException: Error on models.ArtifactEntry.timestamps. mappedBy property [models.TimestampEntry.artifacts] is not a ManyToMany?

EDIT: After having researched more, the problem is clearly the fact that "artifacts" is not the immediate type "List" but a subclass of it. Ebean is not that smart. Any solution to this?

Answer 1

Ok, as I have edited in my previous post, the problem seem to be that EBeans does not read the type hierarchy of the attributes up to match a ManyToMany relation ship. It simply has to match on both classes.

In a first place, I needed to implement this with an empty class extending ArrayList, so that I can register this class with a custom SimpleFormatter (as I did not want to parse all the List in this way).

I ended up removing the "ArtifactsList" and instead, of using a SimpleFormatter with List, I have changed it to use an AnnotationFormatter, so that only only my annotated attribute gets parsed in this custom formatter.