Exception Description: A NullPointerException

Question

I'm working on a project in java with a postgresql database and I'm having a problem when I try to insert data or rather when I commit. It looks like it comes from a problem with ID (game_id) but I do not know what.

Here is the code of my entity :

@Entity
@Cacheable(true)
@Table(name = "game")
@Multitenant(MultitenantType.TABLE_PER_TENANT)
@TenantTableDiscriminator(type = TenantTableDiscriminatorType.SCHEMA, contextProperty = PersistenceUnitProperties.MULTITENANT_PROPERTY_DEFAULT)


public class Game implements Serializable{
    private static final long serialVersionUID = 1L;

    @Id
    @Column(name = "game_id", unique = true, nullable = false)
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Integer gameId;

    @Column(name = "game_title", length = 256)
    private String gameTitle;

    @Temporal(TemporalType.DATE)
    @Column(name = "game_released")
    private Date gameReleased;

    @Column(name = "game_img")
    private Byte[] gameImg;

    @Column(name = "game_desc", length = 3072)
    private String gameDesc;

And here's how I try to insert my data :

EntityManagerFactory emf = Persistence.createEntityManagerFactory("projet_nintendo");
        EntityManager em = emf.createEntityManager();   
        EntityTransaction transac = em.getTransaction();
        transac.begin();



        for(int ii = 0; ii < array.length(); ii++) {
            Game g = new Game();
            g.setGameId(Conversion.stringEnInt(array.getJSONObject(ii).getString("fs_id")));
            g.setGameTitle(array.getJSONObject(ii).getString("title"));

            JSONArray test = array.getJSONObject(ii).getJSONArray("dates_released_dts");
            try {
                SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
                Date parsedDate = dateFormat.parse(test.getString(0));
                g.setGameReleased(parsedDate);
            } catch(Exception e) { 
            }
            em.persist(g);


            System.err.println(array.getJSONObject(ii).getString("pretty_date_s"));
        }

        transac.commit();
        em.close();
        emf.close();

I have this error :

Exception in thread "main" javax.persistence.RollbackException: Exception [EclipseLink-69] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.DescriptorException
Exception Description: A NullPointerException was thrown while extracting a value from the instance variable [gameId] in the object [database.orm.Game].
Internal Exception: java.lang.NullPointerException
Mapping: org.eclipse.persistence.mappings.DirectToFieldMapping[gameId-->game.game_id]
Descriptor: RelationalDescriptor(database.orm.Game --> [DatabaseTable(game)])
    at org.eclipse.persistence.internal.jpa.transaction.EntityTransactionImpl.commit(EntityTransactionImpl.java:157)
    at test.main(test.java:79)
Caused by: Exception [EclipseLink-69] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd)

Could you tell me what I'm doing wrong?

Answer 1

try(EntityManager em = emf.createEntityManager();   
    EntityTransaction transac = em.getTransaction()){

    ...
}
// don't need to close here em.. emf..

Answer 2

Try to remove your @GeneratedValue. Currently you are using

GenerationType.IDENTITY
This GenerationType indicates that the persistence provider must assign primary keys for the entity using a database identity column. IDENTITY column is typically used in SQL Server. This special type column is populated internally by the table itself without using a separate sequence. If underlying database doesn't support IDENTITY column or some similar variant then the persistence provider can choose an alternative appropriate strategy. In this examples we are using H2 database which doesn't support IDENTITY column.

This results in the database assigns a new value automatically for your id field and then EclipseLink have to retrieve it.