JEE Course - JEE Overview

A set of technologies for developing enterprise applications in Java Specified by Sun and the Java Community Process (JCP). Implemented by JEE vendors. Implementations of JEE technologies are provided within Application Servers. Previously named J2EE (until version 1.4) current version is JEE 5. What is JEE ? Copyright © Oded Nissan 2009

The Java Platform Copyright © Oded Nissan 2009 Optional Packages Java Enterprise Edition (JEE) JVM Java Card APIs CardVM Optional Packages Personal Basis Profile Personal Profile Foundation Profile CDC MIDP CLDC KVM * Under development in JCP Java Standard Edition (JavaSE) Java Platform Micro Edition (JavaME TM )

Can use any JEE implementation for development and deployment Use production-quality standard implementation which is free for development/deployment Use high-end commercial JEE products for scalability and fault-tolerance Vast amount of JEE community resources Many JEE related books, articles, tutorials, quality code you can use, best practice guidelines, design patterns etc. Can use off-the-shelf 3rd-party business components Value to developers. Copyright © Oded Nissan 2009

Vendors work together on specifications and then compete in implementations In the areas of Scalability, Performance, Reliability, Availability, Management and development tools, and so on Freedom to innovate while maintaining the portability of applications Do not have create/maintain their own proprietary APIs Value to vendors Copyright © Oded Nissan 2009

The JEE Life Cycle Copyright © Oded Nissan 2009 Creation Assembly Deployment Created by Component Developer Assembled and Augmented by Application Assembler Processed by Deployer Deploy Enterprise Components JEE Container JEE APP JEE Modules

N-tier architecture Comprised of technologies for the business tier the presentation tier and other system services. Runs within the application server and within specific containers (web container, EJB container) within the Application server. The JEE Architecture Copyright © Oded Nissan 2009

Uses the "component and container" model in which container provides system services in a well-defined and as industry standard JEE is a standard that also provides portability of code because it is based on Java technology and standard-based Java programming APIs The JEE Architecture Copyright © Oded Nissan 2009

Single Tier – a simple desktop application. Two Tier – A thin or a fat client and a server. Three Tier – A presentation tier a business tier and a Data tier. About N-Tier Architecture Copyright © Oded Nissan 2009

Presentation tier technologies Servlets 2.5 Java Server Pages (JSP) 2.1 Java Standard Tag Library Java Server Faces (JSF) 1.2 These technologies enable the implementation of a presentation tier in the JEE framework. JEE 5 Technologies Copyright © Oded Nissan 2009

Enterprise Application Technologies Enterprise Java Beans (EJB) 3.0 Java Persistence API (JPA) 1.0 Java Connector Architecture (JCA) 1.5 Java Messaging Services (JMS) 1.1 Java Transaction API (JTA) 1.1 These technologies enable the implementation of the business tier in the JEE framework. JEE 5 Technologies Copyright © Oded Nissan 2009

What is a Web Service ? A web service is a software system identified by a URI, whose public interfaces and bindings are defined and described using XML. Its definition can be discovered by other software systems. These systems may then interact with the Web service in a manner prescribed by its definition, using XML-based messages conveyed by Internet protocols. Web Services Copyright © Oded Nissan 2009

Provide a way to connect heterogonous systems in a Language neutral, platform neutral manner. Use the HTTP protocol to pass messages in the SOAP protocol. Described by a Web Services Description language (WSDL) document. Vendors provide tools to generate web service clients from a WSDL. Web services can be registered and looked up in a UDDI directory. Web Services Copyright © Oded Nissan 2009

Web services are a platform neutral standard, JEE provides its own platform implementation. JEE provide tools for exposing JEE components such as EJBs as web services. JEE also provides tools for generating web service clients from existing WSDL documents and an API for accessing the services. Web Services in JEE Copyright © Oded Nissan 2009

What is EJB ? EJB is a standard JEE technology developed by Sun and the Java community A component architecture for building distributed applications. A server side technology. Usually used to implement the application’s business logic. Enterprise Java Beans (EJB) Copyright © Oded Nissan 2009

Stateless Session beans Stateful Session beans Message driven beans – asynchronous, based on JMS. Entities – Java Persistence architecture (JPA). Object-relational mapping. EJB Types Copyright © Oded Nissan 2009

Messaging systems (MOM) provide De-coupled communication Asynchronous communication Plays a role of centralized post office Benefits of Messaging systems Flexible, Reliable, Scalable communication systems Point-to-Point, Publish and Subscribe JMS defines standard Java APIs to messaging systems Java Messaging Services (JMS) Copyright © Oded Nissan 2009

Defines standard API for integrating J2EE technology with EIS systems CICS, SAP, PeopleSoft, etc. Before Connector architecture, each App server has to provide an proprietary adaptor for each EIS system m (# of App servers) x n (# of EIS's) Adaptors With Connector architecture, same adaptor works with all JEE compliant containers 1 (common to all App servers) x n (# of EIS's) Adaptors Java Connector Architecture (JCA) Copyright © Oded Nissan 2009

Java™ objects which extend the functionality of a HTTP server Dynamic contents generation Better alternative to CGI, NSAPI, ISAPI, etc. Efficient Platform and server independent Session management Java-based Servlets Copyright © Oded Nissan 2009

Enables separation of business logic from presentation Presentation is in the form of HTML or XML/XSLT Business logic is implemented as Java Beans or custom tags Better maintainability, reusability Extensible via custom tags Builds on Servlet technology (JSP is compiled into a Servlet). Java Server Pages (JSP) Copyright © Oded Nissan 2009

<%@ page import="java.util.*" %> <HTML> <BODY> <% System.out.println( "Evaluating date now" ); Date date = new Date(); %> Hello! The time is now <%= date %> </BODY> </HTML> JSP Example Copyright © Oded Nissan 2009

JavaServer Faces technology is a server-side user interface component framework for Java technology-based web applications. Implemented on top of the Servlet and JSP technologies. Makes use of JSP tag libraries. Provides an MVC based web framework. Java Server Faces (JSF) Copyright © Oded Nissan 2009

The Java™ Transaction API (JTA) allows applications to perform distributed transactions, that is, transactions that access and update data on two or more networked computer resources. The JTA specifies standard Java interfaces between a transaction manager and the parties involved in a distributed transaction system: the application, the application server, and the resource manager that controls access to the shared resources affected by the transactions. Java Transaction API Copyright © Oded Nissan 2009

A JTA transaction is controlled by the Java EE transaction manager. JEE support declarative transactions, called Container Managed Transactions. The JTA API can also be used directly by the developer. JTA supports XA transactions. Java Transaction API (JTA) Copyright © Oded Nissan 2009

Pluggable authentication framework Userid/password Smartcard Kerberos Biometric Application portability regardless of authentication schemes underneath JAAS provides authentication scheme independent API Authentication schemes are specified Login configuration file, which will be read by JAAS Java Authentication and Authorizations Service (JAAS) Copyright © Oded Nissan 2009

Java Naming and Directory Interface Utilized by J2EE applications to locate resources and objects in portable fashion Applications use symbolic names to find object references to resources via JNDI The symbolic names and object references have to be configured by system administrator when the application is deployed. JNDI Copyright © Oded Nissan 2009

JMX technology provides a simple, standard way of managing resources such as applications, devices, and services. JMX is used to monitor and manage the JVM itself (the jconsole application is an example). In JEE JMX is used to manage server configuration and resources. All applications server vendors provide JMX beans, which manage their servers. Java management Extensions (JMX) Copyright © Oded Nissan 2009

JEE vendors provide their implementation of JEE technologies within an Application Server. Each application server has its own implementation of JEE standards as well as some proprietary features. Comprised of a Web Container,EJB Container and other server services. JEE Application Servers Copyright © Oded Nissan 2009

WebSphere 7.0 – (IBM) Weblogic 10.0 – (formerly BEA now Oracle) Oracle Application Server 11.0 – Oracle. Sun Application Server 9.0 – (formerly Sun now Oracle) WebSphere leads in market share. Popular Commercial Application Servers (JEE 5 Complient) Copyright © Oded Nissan 2009

JBoss 5.0 - Redhat Glassfish 2.1- (formerly Sun now Oracle) Geronimo 2.1 – (Apache and IBM) JBoss is the most popular,Glassfish’s future is uncertain after the Oracle acquisition, it is said to be very fast after some extensive code rewrites. Popular Open source Application Servers (JEE 5 Compliant) Copyright © Oded Nissan 2009

Tomcat 6.0 – Apache Resin 3.0 – Caucho Provide a web server and a web container without an EJB container JMS and some other features. Very fast and lightweight. Good choice if you are only developing a web application. Popular Open source Web Containers Copyright © Oded Nissan 2009

Provided by Application Server vendors or open source projects. Usually provided as plugins to popular IDEs such as Eclipse or NetBeans. The tools help developers create JEE resources, debug and deploy them. JEE Development Tools Copyright © Oded Nissan 2009

IBM – provides the RAD product (based on Eclipse) for developing for WebSphere. JBoss and Weblogic provide plugins for Eclipse. Sun provides plugins and integration with Netbeans. The Eclipse project provides open source plugins for most application servers. JEE Development Tools Copyright © Oded Nissan 2009

A JEE application is packaged into an EAR file. The EAR file contains Web modules, EJB modules and utility jars. The Web application is packaged into a WAR file, and the WAR file is packaged into the EAR. The EJB’s are packaged into a special jar file which is the EJB module, which is packaged into the EAR file. JEE Application Structure Copyright © Oded Nissan 2009

The JEE Life Cycle- Development Copyright © Oded Nissan 2009 Creation Assembly Deployment Created by Component Developer Assembled and Augmented by Application Assembler Processed by Deployer Deploy Enterprise Components JEE Container JEE APP JEE Modules

JEE Course - JEE Overview

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