1. J2EE Lecture 10: EJB 3.0 Overview
Dr. Ming Qiu
Xiamen University
Software School

2. Mastering EJB3.0, Chap 1
10.1 Overview
What plumbing do you need to build a robust distributed object deployment?
What is EJB, and what value does it add?

3. 10.1 Overview EJB is a server-side component framework
Mastering EJB3.0, Chap 1
10.1 Overview
EJB is a server-side component framework
simplifies the process of building enterprise-class distribute component application in Java

4. 10.1 Overview What is Software Component?
Mastering EJB3.0, Chap 1
10.1 Overview
What is Software Component?
A piece of code written to manifest the behavior of a corresponding abstract concept.
Sounds like Objects, but it is different
Self-contained Entity
Be used in a similar or completely different application
Can live an independent, reusable existence outside of original application
A system can be designed to consist of reusable components

5. 10.1 Overview The Need for Componentization
Mastering EJB3.0, Chap 1
10.1 Overview
The Need for Componentization
Lack of flexibility and interoperability
Component Framework
Common Object Request Broker Architecture (CORBA)
ActiveX/COM
EJB

6. 10.1 Overview Remote method invocation Loading balancing
Mastering EJB3.0, Chap 1
10.1 Overview
Remote method invocation
Loading balancing
Transparent failover
Back-end integration
Transaction
Clustering
Dynamic redeployment

7. 10.1 Overview Each of these aspects can be thought of as a service
Mastering EJB3.0, Chap 1
10.1 Overview
Clean shutdown
Logging and Auditing
Systems management
Threading
Message-oriented middleware
Component life cycle
Resource pooling
Security
Caching
And much…
Each of these aspects can be thought of as a service

8. 10.1 Overview Application Server-Class Software
Mastering EJB3.0, Chap 1
10.1 Overview
Application Server-Class Software
Building Middleware Services from Scratch
Buying Middleware Services via Application Server Software

9. 10.1 Overview Standardization of Component Frameworks
Mastering EJB3.0, Chap 1
10.1 Overview
Standardization of Component Frameworks
More than 50 application servers on the market
Need an agreement to enable any component to run within any application server

10. Mastering EJB3.0, Chap 1
10.1 Overview

11. 10.1 Overview Enterprise JavaBeans Technology
Mastering EJB3.0, Chap 1
10.1 Overview
Enterprise JavaBeans Technology
A standard for developing and deploying server-side distribute components in Java
It is a ubiquitous industry standard
Portability is possible
Rapid application development
EJB is two things in one
Specification
A set of Java Interfaces

12. 10.1 Overview Why Java Interface/implementation separation
Mastering EJB3.0, Chap 1
10.1 Overview
Why Java
Interface/implementation separation
Safe and security
If a thread dies, the application stays up
No memory pointer in java
Memory leaks occur much less often
Cross-platform

13. 10.1 Overview EJB as a Business Tier Component
Mastering EJB3.0, Chap 1
10.1 Overview
EJB as a Business Tier Component
Presentation tier components deal directly with end user or end application
Business tier components perform server-side operation
Such as executing complex algorithm or performing transactional business operation

14. 10.1 Overview EJB components can perform following tasks
Mastering EJB3.0, Chap 1
10.1 Overview
EJB components can perform following tasks
Performing business logic
Access a database
Integrate with other systems
Examples of EJB clients
Application clients
Dynamically generated Web pages
Web service clients

15. Mastering EJB3.0, Chap 1
10.1 Overview

16. 10.1 Overview Distributed Computing: The Foundation of EJB
Mastering EJB3.0, Chap 1
10.1 Overview
Distributed Computing: The Foundation of EJB

17. the Java Platform, Enterprise Edition 10.0 (Java EE)
Mastering EJB3.0, Chap 1
the Java Platform, Enterprise Edition 10.0 (Java EE)

18. the Java Platform, Enterprise Edition 10.0 (Java EE)
Mastering EJB3.0, Chap 1
the Java Platform, Enterprise Edition 10.0 (Java EE)
A uncompleted list of JavaEE Technologies
Enterprise JavaBean(EJB)
Java API for Web Services(JAX-WS)
Java Remote Method Invocation (RMI) and RMI-IIOP
Java Naming and Directory Interface (JNDI)
Java Database Connectivity (JDBC)
Java Transaction API(JTA) and Java Transaction Service(JTS)
Java Message Service (JMS)
Java Servlets
Java Server Pages (JSP)
Java Server Faces (JSF)
Java EE Connector Architecture (JCA)
The Java API for XML Parsing (JAXP)
The Java Architecture for XML Binding (JAXB)
The Java Authentication and Authorization Service (JAAS)

19. 10.2 Pre-EJB 3.0: The World That Was
Mastering EJB3.0, Chap 2
10.2 Pre-EJB 3.0: The World That Was
Briefly introduce the programming and deployment model in EJB2.0
To realize the breadth and depth of enhancements made in EJB3.0

20. 10.2 Pre-EJB 3.0: The World That Was
Mastering EJB3.0, Chap 2
10.2 Pre-EJB 3.0: The World That Was

21. 10.2 Pre-EJB 3.0: The World That Was
Mastering EJB3.0, Chap 2
10.2 Pre-EJB 3.0: The World That Was

22. 10.2 Pre-EJB 3.0: The World That Was
Mastering EJB3.0, Chap 2
10.2 Pre-EJB 3.0: The World That Was

23. 10.2 Pre-EJB 3.0: The World That Was
Mastering EJB3.0, Chap 2
10.2 Pre-EJB 3.0: The World That Was
Differences between the local and the remote interface
The local interface extends javax.ejb.EJBLocalObject instead of javax.ejb.EJBObject
The business method does not throw a java.rmi.RemoteException

24. 10.2 Pre-EJB 3.0: The World That Was
Mastering EJB3.0, Chap 2
10.2 Pre-EJB 3.0: The World That Was

25. 10.2 Pre-EJB 3.0: The World That Was
Mastering EJB3.0, Chap 2
10.2 Pre-EJB 3.0: The World That Was

26. 10.2 Pre-EJB 3.0: The World That Was
Mastering EJB3.0, Chap 2
10.2 Pre-EJB 3.0: The World That Was
Differences between the local and the remote home interface
The local home interface extends javax.ejb.EJBLocalHome instead of javax.ejb.EJBHome
The local home interface methods do not throw java.rmi.RemoteException

27. Mastering EJB3.0, Chap 2

28. 10.2 Pre-EJB 3.0: The World That Was
Mastering EJB3.0, Chap 2
10.2 Pre-EJB 3.0: The World That Was

29. Mastering EJB3.0, Chap 2

30. Mastering EJB3.0, Chap 3

31. 10.2 Pre-EJB 3.0: The World That Was
Mastering EJB3.0, Chap 2
10.2 Pre-EJB 3.0: The World That Was
Dissect EJB 2.x
Development Complexities
Deployment Complexities
Debugging and Testing Complexities

32. 10.3 The New Enterprise JavaBean
Mastering EJB3.0, Chap 3
10.3 The New Enterprise JavaBean

33. 10.3 The New Enterprise JavaBean
Mastering EJB3.0, Chap 3
10.3 The New Enterprise JavaBean
EJB Container
Responsible for managing enterprise bean
Transaction management
Security
Resource and life cycle management
Remote accessibility
Support for concurrent requests
Clustering and load-balancing

34. 10.3 The New Enterprise JavaBean
Mastering EJB3.0, Chap 3
10.3 The New Enterprise JavaBean
Type of Bean
Session beans
model business processes
Stateful & Stateless session bean
Message-driven beans (MDBs)
Similar to session beans, but driven by message
Entity beans (deprecated)
Model business data

35. 10.3 The New Enterprise JavaBean
Mastering EJB3.0, Chap 3
10.3 The New Enterprise JavaBean

36. 10.3 The New Enterprise JavaBean
Mastering EJB3.0, Chap 3
10.3 The New Enterprise JavaBean
RMI-IIOP: The Protocol of Bean
EJB and Location Transparency
JNDI is an enabler of location transparency
Provides a standard API to access different kinds of naming and directory services within a java program
Provides two API
Naming API
Directory API

37. 10.3 The New Enterprise JavaBean
Mastering EJB3.0, Chap 3
10.3 The New Enterprise JavaBean
The EJB 3.0 Simplified API
No home and object interfaces
No component interface
Use of Java metadata annotations
Simplification of APIs for accessing bean’s environment

38. 10.3 The New Enterprise JavaBean
Mastering EJB3.0, Chap 3
10.3 The New Enterprise JavaBean
Elimination of Home and Object Interface
Pre EJB 3.0
The Home interface served as a factory for creating reference to the EJB Object.
The EJB Object Interfaces was to provide client view for an EJB

39. 10.3 The New Enterprise JavaBean
Mastering EJB3.0, Chap 3
10.3 The New Enterprise JavaBean
Elimination of Component Interface
Pre EJB 3.0
Components need to implement javax.ejb.SessionBean or javax.ejb.MessageDrivenBean
Carried the various life cycle method

40. 10.3 The New Enterprise JavaBean
Mastering EJB3.0, Chap 3
10.3 The New Enterprise JavaBean
Use of Annotations
Annotations are used to provide the additional context to program.
Can be applied to various elements in Java
Methods, variables, constructors, package declarations

41. 10.3 The New Enterprise JavaBean
Mastering EJB3.0, Chap 3
10.3 The New Enterprise JavaBean
Annotations and Bean Development
EJB 3.0 is a mix of metadata tags and code structs

42. 10.3 The New Enterprise JavaBean
Mastering EJB3.0, Chap 3
10.3 The New Enterprise JavaBean
Annotations and Deployment Descriptions
EJB 3.0 annotations can be used in lieu of deployment descriptors.
Container Specific Deployment Description
Describe the value-added services of container

43. 10.3 The New Enterprise JavaBean
Mastering EJB3.0, Chap 3
10.3 The New Enterprise JavaBean
The Good, Bad and Ugly of Deployment Annotation
Convenient
Place configuration along with the bean’s logic.
Tricky
When the bean provider and deployer is not the same person.
Simplified Access to environment

44. Package and Deployment of the “New” Bean
Mastering EJB3.0, Chap 3
Package and Deployment of the “New” Bean

45. 10.3 The New Enterprise JavaBean
Mastering EJB3.0, Chap 3
10.3 The New Enterprise JavaBean
Example of EJB 3.0 Bean
The Business Interface

46. 10.3 The New Enterprise JavaBean
Mastering EJB3.0, Chap 3
10.3 The New Enterprise JavaBean
The Bean Class

47. 10.3 The New Enterprise JavaBean
Mastering EJB3.0, Chap 3
10.3 The New Enterprise JavaBean
The Deployment Descriptor

48. 10.3 The New Enterprise JavaBean
Mastering EJB3.0, Chap 3
10.3 The New Enterprise JavaBean
The Client

49. Mastering EJB3.0, Chap 3

50. Summary of Term The enterprise bean instance The business interface
A POJO contains business method implementation of local/remote business interface
The business interface
A plain old java interface that enumerates the business methods exposed by the enterprise bean.
The deployment descriptor
A XML file that specifies the middleware requirements of the bean
The Ejb-jar file
The package unit for enterprise bean
The vendor-specific deployment descriptor
Specify the bean’s need for proprietary container.

51. 10.4 The Java Naming and Directory Interface (JNDI)
Mastering EJB3.0, Appendix A
10.4 The Java Naming and Directory Interface (JNDI)
Naming Service
Associates names with objects
Provides a facility to find an object with a name
Directory Service
A naming service that has been extended and enhanced to provide directory object operations to manipulating attribute

52. 10.4 The Java Naming and Directory Interface (JNDI)
Mastering EJB3.0, Appendix A
10.4 The Java Naming and Directory Interface (JNDI)

53. 10.4 The Java Naming and Directory Interface (JNDI)
Mastering EJB3.0, Appendix A
10.4 The Java Naming and Directory Interface (JNDI)
Problems with Naming and Directory
Different Directory vendors offer different types of services
Lightweight Directory Access Protocol (LDAP)
Network Information System (NIS)
Network Directory System (NDS)
What is JNDI
A System for java client to access Naming and Directory systems
Provide one common interface to disparate directories

54. Mastering EJB3.0, Appendix A
Architecture

55. 10.4 The Java Naming and Directory Interface (JNDI)
Mastering EJB3.0, Appendix A
10.4 The Java Naming and Directory Interface (JNDI)
JNDI in JavaEE
Using JNDI to acquire a reference to the JTA User-Transaction interface
Using JNDI to connect to resource factories, such as JDBC drivers or JMS drivers
Using JNDI for clients and for beans to look up other beans

56. 10.4 The Java Naming and Directory Interface (JNDI)
Mastering EJB3.0, Appendix A
10.4 The Java Naming and Directory Interface (JNDI)
JNDI Concepts
Atomic Name
A simple, basic, indivisible name
In the string /etc/fstab, etc and fstab are atomic names
Compound Name
Zero or more atomic names put together using a specific syntax
/etc/fstab is a compound name

57. 10.4 The Java Naming and Directory Interface (JNDI)
Mastering EJB3.0, Appendix A
10.4 The Java Naming and Directory Interface (JNDI)
Binding
An association of a name with a object
Autoexec.bat  a file
C:\windows  a folder
/usr/people/ed/.cshrc  multiple bindings
Context
A set of zero or more bindings

58. 10.4 The Java Naming and Directory Interface (JNDI)
Mastering EJB3.0, Appendix A
10.4 The Java Naming and Directory Interface (JNDI)
Naming System
A connected set of contexts that use the same name syntax.
Namespace
The set of names contained in a naming system
javax.naming.Name
javax.naming.Context

59. 10.4 The Java Naming and Directory Interface (JNDI)
Mastering EJB3.0, Appendix A
10.4 The Java Naming and Directory Interface (JNDI)

60. 10.4 The Java Naming and Directory Interface (JNDI)
Mastering EJB3.0, Appendix A
10.4 The Java Naming and Directory Interface (JNDI)

61. 10.4 The Java Naming and Directory Interface (JNDI)
Mastering EJB3.0, Appendix A
10.4 The Java Naming and Directory Interface (JNDI)
Composite Name
A name that spans multiple naming systems
Initial Context
The starting point of exploring a namespace
Initial Context Factory
Be implemented by JNDI drivers
churns out initial context
javax.naming.InitialContext

62. 10.4 The Java Naming and Directory Interface (JNDI)
Mastering EJB3.0, Appendix A
10.4 The Java Naming and Directory Interface (JNDI)

63. 10.4 The Java Naming and Directory Interface (JNDI)
Mastering EJB3.0, Appendix A
10.4 The Java Naming and Directory Interface (JNDI)
java.naming.factory.initial
The name of the environment property for specifying the initial context factory to use
java.naming.provider.url
The name of the environment property for specifying the location of the JBoss JNDI service provider the client will use.
java.naming.factory.url.pkgs
The name of the environment property for specifying the list of package prefixes to use when loading in URL context factories.

64. 10.4 The Java Naming and Directory Interface (JNDI)
Mastering EJB3.0, Appendix A
10.4 The Java Naming and Directory Interface (JNDI)
All the environment parameters can be put into jndi.properties file, found on classpath.

65. Mastering EJB3.0, Appendix A