Hibernate HQL casting: java.lang.String cannot be cast to java.lang.Enum

Question

I am getting this problem:

java.lang.String cannot be cast to java.lang.Enum

When I try this HQL:

...
query = em.createQuery("SELECT object from Entity object where object.column = ?");
query.setParameter(1, "X");
return query.getResultList();

Where in DB the type is a Varchar2(x) with a check constraint and the variable in the entity is defined with Enum using the tag @Enumerated(EnumType.STRING):

public enum ColumnEnum {
 X, Y;
}

• mthmulders: Shouldn't it be query.setParameter(1, TypeEnum.X); ?
• Javi Pedrera: I have tried this too, but the received error is the same

Answer 1

If the field is defined as an enum, you must pass an enum as parameter:

query.setParameter(1, TypeEnum.X);

And let Hibernate use the mapping to transform the parameter into a String (if @Enumerated(EnumType.STRING) is uses) or into an int (if @Enumerated(EnumType.ORDINAL) is used).

Answer 2

using following annotation

@Enumerated (value = EnumType.STRING)

OR

Query q = session.createQuery(from Comment c where c.rating = :rating);
q.setParameter(rating,
 Rating.LOW,
 Hibernate.custom(RatingUserType.class));

Answer 3

Here is the example, with two ways.

• First way is to explicitly provide enum
• And a second, more convenient, is to provide a string representation, if a field is enumerated as sring.

---

 public Optional<AffectedAsset> getByEntityId(Long entityId, String assetType) {
 String hql = "FROM AffectedAsset a WHERE a.entityId = :entityId "
 + " AND a.type = :assetType "
 + " ORDER BY id DESC";
 Query query = getSession().createQuery( hql );
 query.setLong( "entityId", entityId );
 // little bit cumbersome : 
 // query.setParameter( "assetType", AffectedAsset.Type.valueOf( assetType.toUpperCase() ) );
 // my preferred way :
 query.setString( "assetType", assetType.toUpperCase() );
 query.setReadOnly( true );
 query.setMaxResults( 1 );
 AffectedAsset res = (AffectedAsset) query.uniqueResult();
 return Optional.ofNullable( res );
}