J2EE Platform: Features, Components, and Case Study, Slides of Computer Science

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A Case Study on the J2EE Platform

History

Transaction Processor

• Solves the following business needs:
  • Guarantees transactional integrity.
    • Several statements executed together as a logical unit.
    • Either all statements execute successfully or none are executed.
    • Uses BEGIN, COMMIT, and ROLLBACK primitives.
  • Manages the execution of programs and the sharing of resources. - Can maintain a pool of running program instances. - Hands instances out to users as needed. - Size of pool based on current user load. - Allows a system to support many more concurrent users than possible if providing duplicate resources for each user.

• From The Java Language: An Overview :

What is Java?

http://java.sun.com/docs/overviews/java/java-overview-1.html

Java: A simple, object-oriented, network-savvy, interpreted, robust, secure, architecture neutral, portable, high-performance, multithreaded, dynamic language.

• Designed to support multiple threads of execution

that can handle different tasks.

• Improves interactive performance of GUI apps.
• Provides built-in language support...
  • Thread class in java.lang package.
    • used to start/run/stop/query threads.
  • Includes set of synchronization primitives...
    • synchronized keyword.
    • wait()and notify() methods.

Java is Multithreaded

“Java makes programming with threads much easier.. .”

Goal

Definitions

J2EE Definitions

• JavaServer Pages (JSP)
  • Provides the ability to “ put snippets of Java code directly into a text-based document. A JSP page is a text-based document that contains two types of text: static template data, which can be expressed in any text-based format such as HTML, WML, and XML, and JSP elements, which determine how the page constructs dynamic content .”
• Servlets
  • Provides the ability to “ define HTTP-specific servlet classes. A servlet class extends the capabilities of servers that host applications accessed by way of a request-response programming model .”

Selected J2EE Component Definitions

• Java Naming and Directory Interface (JNDI)
  • “Provides naming and directory functionality. It provides applications with methods for performing standard directory operations, such as associating attributes with objects and searching for objects using their attributes”.
• Remote Method Invocation (RMI)
  • Provides the ability for “an object running in one Java Virtual Machine (JVM) to invoke methods on an object running in another JVM. RMI provides for remote communication between programs written in the Java programming language”.

Selected J2EE Component Definitions

• Java API for XML – Remote Procedure Call

(JAX-RPC)

• “Uses the SOAP standard and HTTP so client programs can make XML-based remote procedure calls (RPCs) over the Internet. JAX-RPC also supports WSDL so you can import and export WSDL documents”.
• SOAP with Attachments API for Java (SAAJ)
• Provides “ a low-level API upon which JAX-RPC depends. It enables the production and consumption of messages that conform to the SOAP 1. specification and SOAP with Attachments note”.

Selected J2EE Component Definitions

• Common Object Request Broker Architecture

(CORBA)

• An open, vendor-independent architecture and infrastructure created by the Object Management Group (OMG) that allows a CORBA-based program from any vendor, on almost any computer, operating system, programming language, and network, can interoperate with another CORBA-based program from the same or another vendor, on almost any other computer, operating system, programming language, and network.

A paraphrase taken from the CORBA FAQ See http://www.omg.org/gettingstarted/corbafaq.htm

Features

Structure

J2EE Platform Architecture Diagram