Preface

This guide describes the servlet container of the Oracle9iAS Containers for J2EE (OC4J), including discussion of basic servlets, data-access servlets, and servlet filters and event listeners. It also provides an overview of OC4J deployment and configuration, with detailed descriptions of key configuration files.

Because this manual is intended for developers, its content is largely targeted toward users of the OC4J standalone development environment; however, there is ample consideration of OC4J within an Oracle9iAS production environment.

As for Oracle9iAS release 2 (9.0.3), the OC4J servlet container fully complies with the Sun Microsystems Java Servlet Specification, Version 2.3.

This preface contains these topics:

• Intended Audience

• Documentation Accessibility

• Organization

• Related Documentation

• Conventions

Intended Audience

The guide is intended for J2EE developers who are writing Web applications that use servlets and possibly JavaServer Pages (JSP). It provides the basic information you will need regarding the OC4J servlet container. It does not attempt to teach servlet programming in general, nor does it document the Java Servlet API in detail.

You should be familiar with the Sun Microsystems Java(TM) Servlet Specification, Version 2.3. This is especially true if you are developing a distributable Web application, in which sessions can be replicated to servers running under more than one Java virtual machine (JVM).

Because this is a developer's guide, and development and testing are more convenient in an OC4J standalone environment, key aspects of OC4J standalone are discussed, and the assumption is that most developers will be using a standalone environment.

If you are developing applications that primarily use JavaServer Pages, refer to the Oracle9iAS Containers for J2EE Support for JavaServer Pages Developer's Guide.

Documentation Accessibility

Our goal is to make Oracle products, services, and supporting documentation accessible, with good usability, to the disabled community. To that end, our documentation includes features that make information available to users of assistive technology. This documentation is available in HTML format, and contains markup to facilitate access by the disabled community. Standards will continue to evolve over time, and Oracle Corporation is actively engaged with other market-leading technology vendors to address technical obstacles so that our documentation can be accessible to all of our customers. For additional information, visit the Oracle Accessibility Program Web site at

http://www.oracle.com/accessibility/

Accessibility of Code Examples in Documentation

JAWS, a Windows screen reader, may not always correctly read the code examples in this document. The conventions for writing code require that closing braces should appear on an otherwise empty line; however, JAWS may not always read a line of text that consists solely of a bracket or brace.

Accessibility of Links to External Web Sites in Documentation

This documentation may contain links to Web sites of other companies or organizations that Oracle Corporation does not own or control. Oracle Corporation neither evaluates nor makes any representations regarding the accessibility of these Web sites.

Organization

This document contains:

Chapter 1, "Servlet Overview"

Summarizes servlet technology and servlet development in general, introduces the OC4J servlet container, and provides a simple "Hello World" example.

Chapter 2, "Servlet Development"

Describes how the OC4J servlet container supports servlet development and invocation, including a discussion of key development considerations. Provides several complete examples.

Chapter 3, "Deployment and Configuration"

Discusses how to configure the OC4J servlet environment and deploy a Web application in OC4J.

Chapter 4, "Servlet Filters and Event Listeners"

Explains the use of filters to affect servlet input or output, and event listeners to track session and application events and manage resources accordingly. These features are new in the Servlet 2.3 specification.

Appendix A, "Third Party Licenses"

This appendix includes the Third Party License for third party products included with Oracle9i Application Server and discussed in this document.

Related Documentation

See the following additional OC4J documents available from the Oracle Java Platform group:

• Oracle9iAS Containers for J2EE User's Guide

  This book provides some overview and general information for OC4J; primer chapters for servlets, JSP pages, and EJBs; and general configuration and deployment instructions.

• Oracle9iAS Containers for J2EE Support for JavaServer Pages Developer's Guide

  This book provides information for JSP developers who want to run their pages in OC4J. It includes a general overview of JSP standards and programming considerations, as well as discussion of Oracle value-added features and steps for getting started in the OC4J environment.

• Oracle9iAS Containers for J2EE JSP Tag Libraries and Utilities Reference

  This book provides conceptual information and detailed syntax and usage information for tag libraries, JavaBeans, and other Java utilities provided with OC4J.

• Oracle9iAS Containers for J2EE Services Guide

  This book provides information about standards-based Java services supplied with OC4J, such as JTA, JNDI, JMS, JAAS/JAZN, and the Oracle9i Application Server Java Object Cache.

• Oracle9iAS Containers for J2EE Enterprise JavaBeans Developer's Guide and Reference

  This book provides information about the EJB implementation and EJB container in OC4J.

Also available from the Oracle Java Platform group:

• Oracle9i JDBC Developer's Guide and Reference

• Oracle9i SQLJ Developer's Guide and Reference

• Oracle9i JPublisher User's Guide

• Oracle9i Java Stored Procedures Developer's Guide

The following documents are available from the Oracle9i Application Server group:

• Oracle9i Application Server Administrator's Guide

• Oracle Enterprise Manager Administrator's Guide

• Oracle HTTP Server Administration Guide

• Oracle9i Application Server Performance Guide

• Oracle9i Application Server Globalization Support Guide

• Oracle9iAS Web Cache Administration and Deployment Guide

• Oracle9i Application Server Migrating to Release 2 (9.0.3)

The following are available from the JDeveloper group:

• Oracle JDeveloper online help

• Oracle JDeveloper documentation on the Oracle Technology Network:

  http://otn.oracle.com/products/jdev/content.html
  
  

The following documents from the Oracle Server Technologies are also of possible interest:

• Oracle9i XML Developer's Kits Guide - XDK

• Oracle9i Application Developer's Guide - Fundamentals

• Oracle9i Supplied Java Packages Reference

• Oracle9i Supplied PL/SQL Packages and Types Reference

• PL/SQL User's Guide and Reference

• Oracle9i SQL Reference

• Oracle9i Net Services Administrator's Guide

• Oracle Advanced Security Administrator's Guide

• Oracle9i Database Reference

• Oracle9i Database Error Messages

You can obtain the Sun Microsystems Java Servlet Specification, Version 2.3 at the following location:

http://jcp.org/aboutJava/communityprocess/first/jsr053/index.html

For servlet API documentation, refer to the Javadoc available from Sun Microsystems at the following location:

http://java.sun.com/products/servlet/2.3/javadoc/index.html

In North America, printed documentation is available for sale in the Oracle Store at

http://oraclestore.oracle.com/

Customers in Europe, the Middle East, and Africa (EMEA) can purchase documentation from

http://www.oraclebookshop.com/

Other customers can contact their Oracle representative to purchase printed documentation.

To download free release notes, installation documentation, white papers, or other collateral, please visit the Oracle Technology Network (OTN). You must register online before using OTN; registration is free and can be done at

http://otn.oracle.com/

If you already have a user name and password for OTN, then you can go directly to the documentation section of the OTN Web site at

http://otn.oracle.com/docs/index.htm

To access the documentation search engine directly, please visit

http://tahiti.oracle.com

The following resources are available from Sun Microsystems:

• Web site for Java servlet technology, including the latest specifications:

  http://java.sun.com/products/servlet/index.html
  
  

• Web site for JavaServer Pages, including the latest specifications:

  http://java.sun.com/products/jsp/index.html
  
  

Conventions

This section describes the conventions used in the text and code examples of this document. It describes:

• Conventions in Text

• Conventions in Code Examples

Conventions in Text

We use various conventions in text to help you more quickly identify special terms. The following table describes those conventions and provides examples of their use.

Convention	Meaning	Example
Italics	Italic typeface indicates book titles or emphasis, or terms that are defined in the text.	Oracle9i Database Concepts Ensure that the recovery catalog and target database do not reside on the same disk.
UPPERCASE monospace (fixed-width) font	Uppercase monospace typeface indicates elements supplied by the system. Such elements include parameters, privileges, datatypes, RMAN keywords, SQL keywords, SQL*Plus or utility commands, packages and methods, as well as system-supplied column names, database objects and structures, usernames, and roles.	You can specify this clause only for a NUMBER column. You can back up the database by using the BACKUP command. Query the TABLE_NAME column in the USER_TABLES data dictionary view. Use the DBMS_STATS.GENERATE_STATS procedure.
lowercase monospace (fixed-width) font	Lowercase monospace typeface indicates executables, filenames, directory names, and sample user-supplied elements. Such elements include computer and database names, net service names, and connect identifiers, as well as user-supplied database objects and structures, column names, packages and classes, usernames and roles, program units, and parameter values. Note: Some programmatic elements use a mixture of UPPERCASE and lowercase. Enter these elements as shown.	Enter sqlplus to open SQL*Plus. The password is specified in the orapwd file. Back up the data files and control files in the /disk1/oracle/dbs directory. The department_id, department_name, and location_id columns are in the hr.departments table. Set the QUERY_REWRITE_ENABLED initialization parameter to true. Connect as oe user. The JRepUtil class implements these methods.
lowercase italic monospace (fixed-width) font	Lowercase italic monospace font represents place holders or variables.	You can specify the parallel_clause. Run Uold_release.SQL where old_release refers to the release you installed prior to upgrading.

Conventions in Code Examples

Code examples illustrate SQL, PL/SQL, SQL*Plus, or other command-line statements. They are displayed in a monospace (fixed-width) font and separated from normal text as shown in this example:

SELECT username FROM dba_users WHERE username = 'MIGRATE';

The following table describes typographic conventions used in code examples and provides examples of their use.

Convention	Meaning	Example
[ ]	Brackets enclose one or more optional items. Do not enter the brackets.	DECIMAL (digits [ , precision ])
|	A vertical bar represents a choice of two or more options within brackets or braces. Enter one of the options. Do not enter the vertical bar.	{ENABLE | DISABLE} [COMPRESS | NOCOMPRESS]
...	Horizontal ellipsis points indicate either: That we have omitted parts of the code that are not directly related to the example That you can repeat a portion of the code	CREATE TABLE ... AS subquery; SELECT col1, col2, ... , coln FROM employees;
Other notation	You must enter symbols other than brackets, braces, vertical bars, and ellipsis points as shown.	acctbal NUMBER(11,2); acct CONSTANT NUMBER(4) := 3;
Italics	Italicized text indicates place holders or variables for which you must supply particular values.	CONNECT SYSTEM/system_password DB_NAME = database_name
UPPERCASE	Uppercase typeface indicates elements supplied by the system. We show these terms in uppercase in order to distinguish them from terms you define. Unless terms appear in brackets, enter them in the order and with the spelling shown. However, because these terms are not case sensitive, you can enter them in lowercase.	SELECT last_name, employee_id FROM employees; SELECT * FROM USER_TABLES; DROP TABLE hr.employees;
lowercase	Lowercase typeface indicates programmatic elements that you supply. For example, lowercase indicates names of tables, columns, or files. Note: Some programmatic elements use a mixture of UPPERCASE and lowercase. Enter these elements as shown.	SELECT last_name, employee_id FROM employees; sqlplus hr/hr CREATE USER mjones IDENTIFIED BY ty3MU9;