Guest Lecture given on 16/05/2011 to 3rd level students of Thessaloniki's City College CSD

1. Building web
applications with
J2EE
Papapetrou P. Patroklos
Software Engineer / Team Leader at
OTS SA ( www.ots.gr ) since 1997
Part-time lecturer at City College (MSc)
Opensource projects contributor
ppapapetrou76@gmail.com
http://twitter.com/ppapapetrou76
Computer Science Department

2. Overview

J2EE Introduction

J2EE Technologies

J2EE Servers

A working example

Q&A Session
Computer Science Department

3. J2EE Introduction

What does J2EE stand for?

What is its purpose?

Why should I learn to develop Web
Applications using J2EE technologies?

Pros / Cons

Differences with other possible solutions

Required skills
Computer Science Department

4. A glance at J2EE
architecture
Computer Science Department

5. A glance at J2EE
architecture

End-to-End Architecture

N-tier Layers

Components: handle
– Business Logic
– Presentation
– Persistence

Containers
– Vendor-specfic Implementations
– Strictly follow same rules
Computer Science Department

6. A glance at J2EE
architecture

Containers -> work invisible. Provide
services for :
– Security
– Transaction
– Persistence
– Concurrency
– Availability
– Life-cycle Management
Computer Science Department

7. J2EE Development
Lifecycle

Develop components for
– Persistence (Entities)
– Business Logic (EJBs)
– Presentation (JSF, XHTML)

Configure/Prepare deployment descriptors

Build Compoments in packages (JARs, WARs,
EARs)

Deploy packages on Container (J2EE Server)
Computer Science Department

8. J2EE Development
life-cycle - Tools

All target to facilitate building
documentation and management of (Java)
projects

Plethora of choices
– Maven : stands for Accumulator of
Knowledge
– Ant
– Ivy
– Gradle
Computer Science Department

9. J2EE Technologies

Java Persistence API (JPA)

Enterprise Java Beans (EJB)

eXtended Markup Language (XML)

Java Server Faces (JSF)

Java API for XML RPC (JAX-RPC)

eXtensible HyperText Markup Language
(XHTML)

Service Oriented Architecture (SOA)
Computer Science Department

10. Other Related
Technologies

Cascading Style Sheets (CSS)

JavaScript & Jquery

Ajax

Dependency Injection Frameworks
– Google Guice
– Spring Source
– Jboss Weld

... coming more...
Computer Science Department

11. EJB Overview

What is EJB?

A platform for building portable, reusable,
and scalable business applications using
Java

a piece of Java code that executes in a
specialized runtime environment called the
EJB container

EJB is both a component and a framework
Computer Science Department

12. EJB Overview (cont'd)

EJB as a component

Persistence

Entity Beans

Business Logic

Session Beans

Message-Driven Beans
Computer Science Department

13. EJB Overview (cont'd)
EJB as a framework

Out-of-the-box services

Available to all components during
execution via EJB Container

Annotations : The magic wand

Specify services, types and behavior

Service Oriented Architecture

Fast and easy Web Service Creation
Computer Science Department

14. JSF Overview
What is Java Server Faces

A component architecture

A standard – extendable set of UI Widgets

An application infastructure
Basic Characteristics

Event oriented components

Powerful architectures for different Uis
(desktop browsers, mobile devices etc.)

Flexible Navigation System
Computer Science Department

15. JSF Overview (cont'd)
Basic Characteristics

Syncronization with Java Objects through
backing beans

Internationaliztion

Validators & Converters

Several popular implementations
• RichFaces
• IceFaces
• PrimeFaces
Computer Science Department

16. XHTML Overview
Why XHTML instead of HTML?

A more clean and standard way to write
HTML

Take advantages of all XML goodies

Allows a larger percentage of browsers or
code parsers to properly parse pages

Use of Templates to facilitate page
reusability and “inheritance”
Computer Science Department

17. XHTML Overview
Differences with HTML

XHTML elements must be properly nested

XHTML elements must always be closed

XHTML elements must be in lowercase

XHTML documents must have one root
element

Documents can be validated much easier
Computer Science Department

18. XHTML Overview
Differences with HTML

Documents can be transformed via tools
like XSLT into other documents for
consumption by devices like handhelds

Fragments of documents can be retrieved
faster

Text can be stored more effieciently in
object oriented databases
Computer Science Department

19. J2EE Servers
Servers supporting J2EE

Oracle/Sun's Glassfish (
http://glassfish.java.net)

Apache's Jeronimo (
http://geronimo.apache.org)

RedHat's Jboss (http://www.jboss.org )

IBM's Webshpere

Oracle's WebLogic

Caucho's Resin (http://www.caucho.com)
Computer Science Department

20. J2EE Servers
not for EJBs...

Tomcat

Jetty
not for J2EE...

IIS

Apache HTTP
Can you figure out why??
Computer Science Department

21. A working example
MyBlog Application

MySQL as database layer

Entities for persistence layer

Session Beans for business logic layer

XHTML pages for presentation layer
• JSF2 Framework
• Extended by PrimeFaces
Computer Science Department

22. Q&A Session
Thank you
Time for answers!!
Computer Science Department