1. What’s new in JPA 2.0
Alin Burlacu
Java Developer @ Endava
25.11.2011

2. Airplane view
Why ?
 Serializable
 JDBC
 Platform independent
 More OOP like
How ?
 ORM (Object-Relational Mapping)
 Entity manager
 JPQL (Java Persistence Query Language)

3. What’s new
Expanded mapping functionality
Pessimistic locking
Expanded QL
Criteria API
Cache (L2) like a standard (minimal)

4. Expanded mapping functionality
@Access(Type Option)
Mix access modes in a hierarchy
Combine access modes in a single class

5. Expanded mapping functionality
Access Type Option - CODE

6.  @Transient to prevent the field from being
mapped in addition to the property.

7. Expanded mapping functionality
Orphan Removal
Only relationships with single cardinality on
the source side :
 @OneToOne
 @OneToMany

8. Expanded mapping functionality
Orphan Removal - CODE

9. Be aware of object lifecycle

10. Expanded mapping functionality
@ElementCollection
Collections of simple data types mapped in
separate tables.
Map support has been extended so that
maps can have keys and values of basic
types, entities, or embeddables

11. Expanded mapping functionality
@ElementCollection – CODE
(Collection of Basic Types)

12. Expanded mapping functionality
@ElementCollection - CODE
(Map of Basic Types)

13. Expanded mapping functionality
Other
@OrderColumn
@Embeded
@Embedable
@EmbededId
@OneToMany (no join Table)
Hierarchy of embedables
Relations to embedables

15. Pessimistic locking - CODE

16. Pessimistic locking - CODE

17. Expanded QL
 Timestamp literals
SELECT t from BankTransaction t
WHERE t.txTime > {ts „2008-06-
0110:00:01.0‟}
 IN expression may include collection parameter
SELECT emp FROM Employee emp
WHERE emp.project.id IN [:projectIds]
 Non- polymorphic queries
SELECT e FROM Employee e
WHERE CLASS(e) = FullTimeEmployee OR
e.wage = “SALARY”

18. Expanded QL
 Ordered List indexing
SELECT t FROM CreditCard c
JOIN c.transactionHistory t
WHERE INDEX(t) BETWEEN 0 AND 9
 CASE statement
UPDATE Employee e SET e.salary =
CASE e.rating WHEN 1 THEN e.salary * 1.1
WHEN 2 THEN e.salary * 1.05
ELSE e.salary * 1.01
END

19. Criteria API
STRING-BASED CRITERIA - CODE
{
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery c =
b.createQuery(Account.class);
Root acct = c.from(Account.class);
c.select(acct) .where(
cb.equal(acct.get(“name”), “Jim”));
return em.createQuery(c).getResultList();
}

20. Criteria API
STRONGLY TYPED CRITERIA - CODE
{
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<Account> c =
cb.createQuery(Account.class);
Root<Account> acct = c.from(Account.class);
c.select(acct).where(
cb.equal(acct.get(Account_.name),
“Jim”));
Return em.createQuery(c).getResultList();
}

21. Cache (L2) like a standard
(minimal)

23. References
 JSR 317 (http://jcp.org/en/jsr/detail?id=317)
 ProJPA 2 Mastering the Java™ Persistence API by
Mike Keith and Merrick Schincariol
 Beginning Java™ EE 6 Platform with GlassFish™ 3 by
Antonio Goncalves
 http://www.infoq.com/presentations/whats-new-and-
exciting-in-jpa-20
 http://en.wikibooks.org/wiki/Java_Persistence/What_is_
new_in_JPA_2.0%3F
 http://wiki.eclipse.org/EclipseLink/Examples/JPA#JPA_
2.0
 http://www.developer.com/features/article.php/3892261/
JPA-20-Cache-Vs-Hibernate-Cache-Differences-in-
Approach.htm

24. Thank you