EJB 3.0 introduced a simplified programming model for enterprise Java with plain old Java objects (POJOs), dependency injection, and metadata-driven configuration. The new features include support for POJO session beans with simplified lifecycles, the Java Persistence API (JPA) for object-relational mapping, and the ability to define interceptors for cross-cutting concerns.

1. EJB 3.0 Peter Antman, CTO, 2006 - 2007 Mogul

4. dependency injection of resources, such as other EJB:s or Data Sources

7. security

8. resource management

9. remoting

11. An Object/Relational persistence specification: Java Persistence API (JPA)

12. Session- and message driven beans are ordinary Java Beans: no inheritance from javax.ejb. beans

13. No requirement to implement callback interfaces

14. No more home interfaces

15. Remote business interface is an ordinary interface, no need to extend java.rmi.Remote

16. No need for remote methods to throw RemoteException

17. Local business interface is an ordinary interface

18. Bean should/may implement its interfaces

19. Simplified Exception handling by reducing need of checked exceptions

20. Business and lifecycle interceptors

22. Add @Remote to interface or bean to make the interface Remote @Stateless @Remote public class MyBean implements My

24. These may not be the same interface

25. They may however inherit a common parent

30. Supports @PostConstruct and @PreDestroy annotation

31. May use @MessageDriven annotation to configure itself

32. May use one or more @ActivationConfigProperty annotation for configuration @MessageDriven(activationConfig = { @ActivationConfigProperty(propertyName="destinationType", propertyValue="javax.jms.Queue"), @ActivationConfigProperty(propertyName="destination", propertyValue="queue/mdb") }) public class CalculatorBean implements MessageListener { public void onMessage (Message msg) {

36. Have optional attributes

37. @javax.ejb.EJB injects references to other session beans

38. @javax.annotation.Resource injects resources such as environment entries or data base connections

39. @Resource may also be used to get an EJB context injected

42. Defaults to simple naming scheme (CLASSNAME/FIELDNAME)

47. Defaults to REQUIRED

51. An interceptor intercept/filters calls to bean business methods

52. An interceptor is annotated with @javax.interceptor.AroundInvoke

53. An interceptor intercepts all methods that has not excluded interception

54. An interceptor may be defined as a method in a bean @Stateless public class MyBean { @AroundInvoke public Object log(InvocationContext inv) throws Exception { // Do stuff return inv.proceed(); }

58. Declares both ordinary and RuntimeExceptions as application exceptions

59. Declarative statement if an application exception shall cause a rollback @ApplicationException(rollback=true) MyAppException extends RuntimeException {

62. API for persistence

65. Metadata annotations (or xml file)

66. EntityManager

67. Query

68. persistence.xml

70. must have a public no arg constructor

71. have JavaBeans properties

72. supports inheritance and polymorphism

73. persistent state represented by instance variables

74. Must have a primary key

75. can be attached/detached/reattached to persistence storage.

76. are annotated with at least @Entity and @Id annotation

78. one-to-many

79. many-to-one

80. many-to-many

81. Simple entity which uses default values @Entity public class Person implements Serializable { private long id; private String firstName; private String lastName; @Id public long getId(){ return id;} public void setId(long id) {this.id = id;} public String getFirstName() { return firstName;} public void setFirstName(String fn) {this.firstName = fn;} //... }

82. More complex entity @Entity @Table(name=”PERSON_TABLE”, uniqueConstraints=”PERSON_MAIL”) public class Person implements Serializable { //... @Id @GeneratedValue public long getId(){ return id;} public void setId(long id) {this.id = id;} @Column(name=”PERSON_FIRST”, nullable=false, length=20) @Basic(fetch=FetchType.LAZY) public String getFirstName() { return firstName;} public void setFirstName(String fn) {this.firstName = fn;} //... @OneToOne(fetch=FetchType.LAZY) @JoinColumn(name=”ADDRESS_ID”) public Address getAddres() {} }

86. @PostPersist

87. @PostLoad

88. @PreUpdate

89. @PostUpdate

90. @PreRemove

91. @PostRemove

95. must be access through the new javax.persistence.EntityManager service

97. An entity is managed as long it is attached to a persistence context

98. When a persistence context is closed all entities it manages becomes detatched

99. A persistence context is only valid during a transaction, its is closed when transaction commits

101. The beans are not detached

102. Its possible to follow lazy relations

103. In EJB it may only be used in stateful session beans

104. The extended context is closed when the stateful bean is removed @PersistenceContext(type=PersistenceContextType.EXTENDED) private EntityManager manager;

110. INNER JOIN

111. LEFT JOIN

112. Fetch Joins (prefetch lazy relations)

113. DISTINCT

114. LIKE

115. MEMBER OF (a collection)

116. Functional expressions such as LOWER, UPPER

117. ORDER BY, GROUP BY, HAVING

118. Subqueries

119. Bulk update and delete

120. Native Queries

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