Null pointer exception wiht @StaticMetamodel

ibarash · **Joined:** Sun Sep 04, 2011 10:26 am **Posts:** 4

Hello, I am trying to create a type-safe criteria query.

this is my function:

Code:

@Override
   public List<QuestionnaireClient> read(String questionnaireId) {
      CriteriaQuery<QuestionnaireClient> criteria = getEntityManager().getCriteriaBuilder().createQuery(QuestionnaireClient.class);
      
      Root<QuestionnaireClient> client = criteria.from(QuestionnaireClient.class);
      
      Path<String> questionnaireIdPath = client.get(QuestionnaireClient_.questionnaireId);
      
      criteria.where(getEntityManager().getCriteriaBuilder().equal(questionnaireIdPath, questionnaireId));
      
      TypedQuery<QuestionnaireClient> query = getEntityManager().createQuery(criteria);
      
      List<QuestionnaireClient> pesristedClients = query.getResultList();

      return pesristedClients;
   }

I get a null pointer exception on line 3:
Path<String> questionnaireIdPath = client.get(QuestionnaireClient_.questionnaireId);

Now, this is the entity:

Code:

@Entity
@Table(name = "clients")
@Inheritance(strategy = InheritanceType.JOINED)
public class QuestionnaireClient implements Serializable {

   /* --- Members --- */

   /** Serial version unique id */
   private static final long serialVersionUID = 1L;

   @Id
   @GeneratedValue(generator = "uuid")
   @GenericGenerator(name = "uuid", strategy = "uuid")
   private String id;

   @Version
   private int version;

   @Enumerated(EnumType.STRING)
   private IdType idType;

   private String clientId;

   private String fullName;

   private String shortPassportId;

   @Enumerated(EnumType.STRING)
   private RelationToAccount accountRelation;

   private boolean isParticipating;

   private boolean isEditable;

   private String questionnaireId;

This is the meta model class:

Code:

@StaticMetamodel(QuestionnaireClient.class)
public class QuestionnaireClient_ {

   public static volatile SingularAttribute<QuestionnaireClient, Long> serialVersionUID;
   public static volatile SingularAttribute<QuestionnaireClient, String> id;
   public static volatile SingularAttribute<QuestionnaireClient, Integer> version;
   public static volatile SingularAttribute<QuestionnaireClient, String> idType;
   public static volatile SingularAttribute<QuestionnaireClient, String> clientId;
   public static volatile SingularAttribute<QuestionnaireClient, String> fullName;
   public static volatile SingularAttribute<QuestionnaireClient, String> shortPassportId;
   public static volatile SingularAttribute<QuestionnaireClient, String> accountRelation;
   public static volatile SingularAttribute<QuestionnaireClient, Boolean> isParticipating;
   public static volatile SingularAttribute<QuestionnaireClient, Boolean> isEditable;
   public static volatile SingularAttribute<QuestionnaireClient, String> questionnaireId;
}

I also tried to create the metamodel class with only the wanted line which is:
public static volatile SingularAttribute<QuestionnaireClient, String> questionnaireId;

I got the same result.

Can anyone please help me?

Thank you,
Ido

vitorsouza · **Posted:** Thu Nov 10, 2011 10:39 am

I recently had this problem and I managed to solve it. I posted about it in a Stack Overflow question: http://stackoverflow.com/questions/3854 ... 07#8081107 -- see if it is of any help to you...

- Vítor Souza