import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;

@Entity
public class DemoEntity implements Serializable {

  @Id
  @Column
  private byte[] id;

  @Column
  private String name;

  public DemoEntity() {

  }

  public void setId(byte[] id) {
    this.id = id;
  }

  public byte[] getId() {
    return id;
  }

  public void setName(String data) {
    this.name = data;
  }

  public String getName() {
    return name;
  }

}

  /**
   * Tries to remove two records from database.
   *
   * Second remove operation throws NPE. It is marked as expected for
   * demonstration purpose.
   */
  @Test(expected = NullPointerException.class)
  public void testMultipleDeletionsNPE() {
    EntityManager em = null;

    try {
      em = prepareEntityManager();
      Query q = em.createQuery("SELECT s FROM DemoEntity s", DemoEntity.class);
      List<DemoEntity> results = q.getResultList();

      em.remove(results.get(0));
      em.remove(results.get(1)); // NPE

      em.getTransaction().commit();

      assertEquals(1, q.getResultList().size());
    } finally {
      closeEntityManager(em);
    }
  }

  /**
   * Tries to update two records in database.
   *
   * Throws RollbackException caused by NPE during commit. It is marked as expected for
   * demonstration purpose.
   */
  @Test(expected = RollbackException.class)
  public void testMultipleUpdatesNPE() {
    EntityManager em = null;

    try {
      em = prepareEntityManager();
      Query q = em.createQuery("select s from DemoEntity s", DemoEntity.class);
      List<DemoEntity> results = q.getResultList();

      results.get(0).setName("Different 0");
      results.get(1).setName("Different 1");

      em.getTransaction().commit(); // RollbackException caused by NPE

      List<DemoEntity> check = q.getResultList();
      assertEquals("Different 0", check.get(0).getName());
      assertEquals("Different 1", check.get(1).getName());
    } finally {
      closeEntityManager(em);
    }
  }

...
	@Override
	public int compareTo(Object other) {
		final EntityAction action = (EntityAction) other;
		//sort first by entity name
		final int roleComparison = entityName.compareTo( action.entityName );
		if ( roleComparison != 0 ) {
			return roleComparison;
		}
		else {
			//then by id
			return persister.getIdentifierType().compare( id, action.id );
		}
	}
...

...
	public PrimitiveByteArrayTypeDescriptor() {
		super( byte[].class, ArrayMutabilityPlan.INSTANCE );
	}
...

...
	protected AbstractTypeDescriptor(Class<T> type, MutabilityPlan<T> mutabilityPlan) {
		this.type = type;
		this.mutabilityPlan = mutabilityPlan;
		this.comparator = Comparable.class.isAssignableFrom( type )
				? (Comparator<T>) ComparableComparator.INSTANCE
				: null;
	}
...

  /**
   * Removes two records from database.
   *
   * Flush operation placed between removing each entity prevent NPE throwing.
   */
  @Test
  public void testMultipleDeletions() {
    EntityManager em = null;

    try {
      em = prepareEntityManager();

      Query q = em.createQuery("select s from DemoEntity s", DemoEntity.class);
      List<DemoEntity> results = q.getResultList();

      em.remove(results.get(0));
      em.flush(); // clear deletions queue - prevent throwing NPE
      em.remove(results.get(1));

      em.getTransaction().commit(); //implicitly calls flush

      assertEquals(1, q.getResultList().size());
    } finally {
      closeEntityManager(em);
    }
  }

  /**
   * Updates two records in database.
   *
   * Flush operation placed between changing each entity prevents NPE throwing.
   */
  @Test
  public void testMultipleUpdates() {
    EntityManager em = null;

    try {
      em = prepareEntityManager();
      Query q = em.createQuery("select s from DemoEntity s", DemoEntity.class);
      List<DemoEntity> results = q.getResultList();

      results.get(0).setName("Different 0");
      em.flush();
      results.get(1).setName("Different 1");

      em.getTransaction().commit(); //implicitly calls flush

      List<DemoEntity> check = q.getResultList();
      assertEquals("Different 0", check.get(0).getName());
      assertEquals("Different 1", check.get(1).getName());
    } finally {
      closeEntityManager(em);
    }
  }

<persistence  ...>
  <persistence-unit name="DEMO" transaction-type="RESOURCE_LOCAL">
	<provider>org.hibernate.ejb.HibernatePersistence</provider>
	...
  </persistence-unit>
</persistence>

...
    <dependency>
      <groupId>org.hibernate</groupId>
      <artifactId>hibernate-entitymanager</artifactId>
      <version>4.2.17.Final</version>
    <dependency>
...