Preface

Who Should Read This Guide

This Guide has been written for several audiences. They include

• Java developers

• Oracle developers not familiar with Java

• managers

Java developers who are used to a Java J2EE environment should have very little trouble developing applications for the Oracle Servlet Engine. However, since the OSE runs in a virtual JVM in an Oracle database session, there are concepts and procedures discussed in this Guide that you should understand to facilitate OSE application development.

Oracle database developers who are familiar with PL/SQL and other non-Java programming environments should read the overview of Java and object-oriented concepts discussed in the first part of this Guide. For more information about Java, see "Information Resources".

Chapters 1 and 2 of this Guide should give managers a good overview of the capabilities of the Oracle Servlet Engine (OSE). As a manager, you might have purchased Oracle9i for reasons other than Java development within the database. But if you do want to know more about Oracle9i Java features, see the Oracle9i Java Developer's Guide for a management perspective on Java development.

The OSE is different from a Web server such as Apache with a servlet engine, e.g. Tomcat. In these cases, the servlet server runs in a JVM in an operating system process, not in a JVM in a database session. There are some special concepts that apply to the OSE in the Oracle JVM (OJVM), such as the method of database access, how Java servlet classes and JavaServer Pages are loaded, and the way that sessions are handled. Becoming familiar with the OSE/OJVM way of doing things is a prerequisite to developing successful applications of the OSE.

If you are developing applications that primarily use JavaServer Pages, read the OracleJSP Support for JavaServer Pages Developer's Guide and Reference.

How to Read This Guide

This Guide describes the Oracle Servlet Engine when it runs in an Oracle server. This Guide does not attempt to teach servlet programming, nor does it document the Java Servlet API. To learn about these topics, see the documentation available from Sun Microsystems, or look at one of the trade books on servlet programming.

This Guide contains the following chapters and appendices:

Chapter  1, "Oracle Servlet Engine Overview"	Introduces the product and describes some of its advantages over alternative servlet engines.
Chapter  2, "Oracle Servlet Engine Concepts"	Describes the way the OSE operates, and how it differs from other servlet engines.
Chapter  3, "OSE Configuration and Examples"	Provides specific instructions on configuring OSE services, domains, and servlet contexts. Includes many examples.
Chapter  4, "An Apache Module for OSE"	Describes the Oracle HTTP Server module that directs requests for servlets from Apache to the OSE.
Chapter  5, "Configuring mod_ose"	Tells you how to configure mod_ose.
Chapter  6, "Calling EJBs"	Describes a demonstration application that calls an EJB from a servlet.
Chapter  7, "Oracle Servlet Engine Security"	Covers all aspects of security with the OSE.
Chapter  8, "Oracle WAR Deployment"	Describes how to create servlet contexts, and deploy servlets within them, using a Web Archive file.
Chapter  9, "Writing PL/SQL Servlets"	Describes how to write servlets using PL/SQL and the PL/SQL gateway.
Appendix A, "Abbreviations and Acronyms"	A comprehensive list of network- and Java-related acronyms.

Oracle8i Release 3 Users

This Guide has been rewritten extensively from the Oracle8i Release 3 version of the Guide.

Nevertheless, if you are using the Oracle8i Release 3 version of the OSE, almost all of the descriptions and instructions in this Guide also apply to your release. There have been a few additions in functionality for the Oracle9i OSE in OJVM release, mostly in the area of improvements for the Apache module mod_ose. New Oracle9i functionality is indicated as such.

Conventions

This book generally uses UNIX syntax for file paths and shell variables. In most cases file names and directory names are the same for Windows NT, unless otherwise noted. The notation $ORACLE_HOME indicates the full path of the Oracle home directory. It is equivalent functionally to the Windows NT environment variable %ORACLE_HOME%, though of course the Oracle installation paths are different between NT and Solaris or other UNIX flavors.

This Guide uses the following additional conventions.

Convention	Meaning
italicized regular text	Italicized regular text is used for emphasis or to indicate a term that is being defined or will be defined shortly.
. . .	Horizontal ellipsis points in sample code indicate the omission of a statement or statements or part of a statement. This is done when you would normally expect additional statements or code to appear, but such statements or code would not be related to the example.
code text	Code text (Courier font) within regular text indicates class names, object names, method names, variable names, Java types, Oracle datatypes, file names, URL or URI fragments, and directory names.
%	At the beginning of a command, indicates an operating system shell prompt.
$	At the beginning of a command, indicates an Oracle JVM session shell prompt.
SQL>	At the beginning of a command, indicates a SQL*Plus prompt.

Information Resources

To understand the Oracle JVM programming environment, see the Oracle9i Java Developer's Guide.

Managing the OSE requires that you issue a number of commands. Some of these are issued at the operating system level, at the shell (command processor) level. For example, to load a Java servlet class into Oracle9i you use the loadjava command from the shell prompt. To publish a servlet class to the OSE, you use the OJVM session shell, and in the session shell you issue the publishservlet command.

Each of these commands is described briefly in this Guide. But for a complete description of the commands and all their parameters, see the Oracle9i Java Tools Reference.

The following table lists some sources of information about Java, Java Web servers, and other related topics that are available on the World Wide Web.

Location	Description
http://www.oracle.com/java	The latest offerings, updates, and news for Java within the Oracle9i database. This site contains FAQs, updated JDBC drivers, SQLJ reference implementations, and white papers that detail Java application development. In addition, you can download Java tools (on a try-and-buy basis) from this site.
http://java.sun.com/	The Sun Microsystems Web site that is the central source for Java. This site contains Java products and information, such as Javadoc, tutorials, book recommendations, and the Java Developer's Kit (JDK).
http://java.sun.com/docs/books/jls http://java.sun.com/docs/books/vmspec	The Oracle9i JVM implements the Java Language specification (JLS) and the Java virtual machine (JVM) specification, as described here.
http://java.sun.com/products/...	The Oracle Servlet Engine is compliant with the Servlet 2.2 specification, part of the J2EE specification. These specifications are available here.
http://www.apache.org	Information and documentation on the Apache Web server (a component of the Oracle HTTP Server). The Oracle HTTP Server is used together with mod_ose (see Chapter  4, "An Apache Module for OSE") to access the OJVM OSE.
comp.lang.java.programmer comp.lang.java.databases	Internet newsgroups can be a valuable source of information on Java from other Java developers. We recommend that you monitor these two newsgroups. Note: Oracle monitors activity on some of these newsgroups and posts responses to Oracle-specific issues.

Your local or on-line bookseller has many useful Java references. You can find another listing of materials that are helpful to beginners, and that you can use as general references, in the .OracleJSP Support for JavaServer Pages Developer's Guide and Reference

Documentation Accessibility

Oracle's goal is to make our products, services, and supporting documentation accessible to the disabled community with good usability. 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 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/

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.