Chapter 1 J2EE Overview by sus16053

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									  Chapter 1:
J2EE Overview




                1
                   Objectives
• To learn the components of J2EE

• To learn J2EE concepts
  – Architecture
  – J2EE APIs
  – Packaging
  – Roles



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          A Brief History of the
             Java Platform
•   1995: Version 1.0 (Sun Microsystems)
•   1997: Version 1.1
•   1998: Java 2 platform
•   1999: J2SE, J2EE, and J2ME
•   2001: Version 1.3 of J2SE
•   2002: Version 1.4
•   2002: Version 1.3 of J2EE
•   2004: Version 1.4 of J2EE
• 2006: Version 5.0 of JEE
                                           3
          What is J2EE/JEE?
• A set of integrated Java APIs that enable
  client-server Web applications
• Originally defined by Sun Microsystems
  – Java Community Process now includes many
    software vendors including IBM, BEA, Sybase, etc.
• J2EE is not the same as J2SE
• J2EE has many versions
  – J2EE 1.2
  – J2EE 1.3
  – J2EE 1.4 (used in this course)
     • Supported in JBoss 4.x
  – JEE 5.0
                                                        4
     The Three Editions of the
         Java 2 Platform

• The Java 2 platform comes in three versions:
  – Java 2 Standard Edition (J2SE)
  – Java 2 Enterprise Edition (J2EE)
  – Java 2 Micro Edition (J2ME)




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     Reasons for Using J2EE
• Hardware Independence
  – Works with different hardware and software
    platforms
• Code Separation
  – Layered architecture, MVC
• Compatibility
  – different versions of APIs work together
• Scalability
  – Pluggable components; multiple servers
• Tool Independence
  – Multiple vendors to choose from
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MVC/ N-tier Architecture
             J2EE Server
Client




                       Enterprise
                                    7
            J2EE Architecture




Source: Sun Microsystems        8
                Key J2EE APIs
•   Component Technologies
    – Servlets
    – Java Server Pages (JSP)
    – Enterprise Java Beans (EJB)
•   Standard Services
    – Java Database Connectivity (JDBC API)
    – Java Naming and Directory Interface
      (JNDI)
    – Java Transaction API (JTA)
•   Other Services
    – HTTP, HTTPS, RMI-IIOP, JMS, JavaMail    9
J2EE Packaging into Archive
          Files




                              10
Containers in the N-Tier J2EE
        Architecture




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      J2EE Development Roles
• Product Provider
  – Vendors who provide J2EE server
     • E.g., IBM Websphere, BEA WebLogic, Sybase EAServer)
• Tool Provider
  – Vendors who provide the J2EE IDE
     • E.g., IBM WSAD, Borland JBuilder, Oracle JDeveloper 10g
• Application Component Provider
  – Enterprise Bean developer (focus of this course)
  – Web Component developer (focus of this course)
  – Application Client developer
                                                                 12
   J2EE Development Roles (2)
• Application Assembler
  – Team leader or project architect
• Deployer
  – Install and configure the J2EE application
• System Administrator
  – Maintains the fixes for the J2EE server
  – Performance testing


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                References
• Introduction to JEE 5.0
  – http://java.sun.com/developer/technicalArticle
    s/J2EE/intro_ee5/
• J2EE 1.4 Documentation
  – http://java.sun.com/j2ee/1.4/docs/




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