JPA: Invalid-Key Error when using the Criteria API

I always get the same error when using the criteria API:

    Local Exception Stack:
Exception [EclipseLink-6075] (Eclipse Persistence Services - 2.0.1.v20100213-r6600): org.eclipse.persistence.exceptions.QueryException
Exception Description: Object comparisons can only use the equal() or notEqual() operators.  Other comparisons开发者_如何转开发 must be done through query keys or direct attribute level comparisons.
Expression: [
Relation operator  LIKE
   Query Key rootId
      Base de.uni.entities.Diary
   Constant Testaccount]
Query: ReportQuery(referenceClass=Diary )

The code with the criteria API is the following:

        ....
    CriteriaBuilder cb = getEm().getCriteriaBuilder();
    CriteriaQuery<User> cq = cb.createQuery(User.class);

    // Restrictions
    Predicate[] predicate = new Predicate[1];

    // From-clause
    Root<User> root2R = cq.from(User.class);
    predicate[0] = cb.like(root2R.<String> get("rootId"), id);

    Join<Clazz, Diary> friends2R;
    friends2R = root2R.join("diaries");

    cq.where(predicate);

    // Select-clause
    cq.select((Selection<? extends Clazz>) friends2R);

    Query query = getEm().createQuery(cq);

    List<Object> data = query.getResultList();

    return data;

}

The problem exists because of the following two lines: " Join friends2R; friends2R = root2R.join("diaries");"

Without the mapping (with an adjusted select-clause) i would get the searched User with the fitting rootId, so that there occurs no error. But now i wanna map the User with the Diaries and show all diaries of the User-entity. But it always ends in the error ahead. Whether i use "like" or "equal", it doesn't work.

The generell code shouldn't have an error, because i'm using the same code already to get all mapped Users of a User (many to many relation) => no problem.

I just don't understand, why this error occurs and especially why it mentions the Diary as Base although the user should be mentioned as the base-class...and the id is right too and also appears so in the database...

I really hope that you can help me, thanks in advance!

How is rootId mapped, using a Basic, or OneToOne? Seems to be a bug, please log the bug on EclipseLink.

Your code does not seem correct though, the

CriteriaQuery cq = cb.createQuery(User.class);

should be,

CriteriaQuery cq = cb.createQuery(Diary.class);

should it not?

Doesn't Diary also have a relationship to User? You could just query Diary where its user has the id.