Preface

Who Should Read This Book

This book has been written for the following audiences:

• Management--You may have purchased Oracle9i for reasons other than Java development within the database. However, if you want to know more about Oracle9i Java features, see "Overview of Oracle9i Java Documentation" for a management perspective.

• Non-Java Developers--Oracle database programming consists of PL/SQL and other non-Java programming. For experienced PL/SQL developers who are not familiar with Java, a brief overview of Java and object-oriented concepts is discussed in the first part of Chapter1, "Introduction to Java in Oracle9i". For more detailed information on Java, see "Java Information Resources" at the end of this Preface.

• Java Developers--Pure Java developers are used to a Java environment that follows the Sun Microsystems specification. However, when Java is combined in the database, both Java and database concepts merge. Thus, the Java environment within Oracle9i is expanded to include database concerns. The bulk of this book discusses how to execute Java in the database. The following outlines the two viewpoints that arise from this merge:
  • Java environment--Note that Oracle9i delivers a compliant Java implementation--any 100% pure Java code will work. Oracle9i JVM affects your Java development in the way you manage your classes, and the environment in which your classes exist. For example, the classes must be loaded into the database. In addition, there is a clearer separation of client and server in the Oracle9i model.

  • Database environment--You need to be aware of database concepts for managing your Java objects. This book gives you a comprehensive view of how the two well-defined realms--the Oracle9i database and the Java environment--fit together. For example, when deciding on your security policies, you must consider both database security and Java security for a comprehensive security policy.

Java API Programming Models

The building blocks that Java developers use in Oracle9i are as follows:

• Java stored procedures--You can develop Java applications that are stored in the database. Once loaded, these procedures can be invoked from SQL, PL/SQL, or as triggers. See the Oracle9i Java Stored Procedures Developer's Guide. for more information.

• JDBC and SQLJ--You can write a Java application that accesses SQL data from the client, or directly on the server.

• Distributed Java CORBA or EJB applications--You can develop distributed EJB or CORBA applications that are loaded and invoked in the database.

Each of these models is briefly discussed in Chapter1, "Introduction to Java in Oracle9i" and examples are given in Chapter3, "Invoking Java in the Database". Both of these chapters should help you decide which model to use for your particular application. Once you decide on the appropriate model, examine the appropriate developer's guide for in-depth information on each model. For example, if you decide to use Java stored procedures, examine Oracle9i Java Stored Procedures Developer's Guide.

Java Information Resources

The following table lists the sources of current information discussed in the Java programming documentation suite:

Location	Description
http://www.oracle.com/java	The latest offerings, updates, and news for Java within the Oracle9i database. This site contains Frequently Asked Questions (FAQ), updated JDBC drivers, SQLJ reference implementations, and white papers that detail Java application development. In addition, you can download try-and-buy Java tools 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 tutorials, book recommendations, and the Java Developer's Kit (JDK). The JDK is located at http://java.sun.com/products
http://java.sun.com/docs/books/jls http://java.sun.com/docs/books/vmspec	The Oracle9i Java Server is based on the Java Language Specification (JLS) and the Java virtual machine (JVM) specification.
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.

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.

JAWS, a Windows screen reader, may not always correctly read the Java code examples in this document. The conventions for writing Java 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.

For additional information, visit the Oracle Accessibility Program web site at http://www.oracle.com/accessibility/.